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African Trypanosomiasis (sleeping sickness) African trypanosomiasis is a parasitic infection transmitted by the bite of the tsetse fly. The tsetse fly lives only in rural areas in Africa, between the 15th parallel north and the 20th parallel south, chiefly in dense vegetation along rivers, lakes, and streams and in the woodlands and thickets of the savannah. (See Geographical distribution of African trypanosomiasis by the World Health Organization.) The parasite is inoculated into a human or animal as the tsetse fly takes a blood meal. Early symptoms may include fever, weakness, headache, joint pains, rash, itching, edema, and enlargement of lymph nodes. In the late stages of the disease, when the parasite has invaded the nervous system, the sufferer becomes apathetic, has difficulty concentrating, and experiences sudden mood swings. In the final stages, the victim becomes so lethargic that even simple activities such as eating and speaking require extraordinary effort. The person ultimately becomes comatose and dies. There are two types of African trypanosomiasis, caused by different parasites: Trypanosoma brucei gambiense, which causes a chronic infection that progresses slowly over years and which is found chiefly in western and central Africa, and Trypanosoma brucei rhodesiense, which progresses rapidly over several weeks and which occurs primarily in eastern and southern Africa. Treatment depends upon the stage of disease. Many of the drugs used to treat African trypanosomiasis have significant toxicities. The best means of prevention is to avoid areas infested with tsetse flies, which are usually known to local inhabitants. Insect repellents are ineffective. Tsetse flies are attracted to moving vehicles and dark, contrasting colors, and can bite through lightweight clothing. Travelers at risk should therefore wear long sleeves and long pants of medium weight fabric in neutral colors that blend with the environment. From the World Health Organization (WHO) African trypanosomiasis: the disease African trypanosomiasis: brief history African trypanosomiasis: geographical distribution Surveillance and control of African trypanosomiasis (PDF) African trypanosomiasis fact sheet From the Centers for Disease Control (CDC) African trypanosomiasis Fact Sheet on East African Trypanosomiasis Fact Sheet on West African Trypanosomiasis African Trypanosomiasis (life cycle, geographic distribution, clinical features, diagnosis) From Health Canada African Trypanosomiasis or Sleeping Sickness From Eurosurveillance Imported Human African Trypanosomiasis in Europe, 2005-2009 From Emerging Infectious Diseases African Trypanosomiasis in Travelers Returning to the United Kingdom, by David A.J. Moore et al. From TDR African trypanosomiasis Anthrax Anthrax is caused by a bacterium known as Bacillus anthracis, which infects grazing herbivores, chiefly cattle, sheep, goats, and horses. When exposed to oxygen, the organism forms spores, which are resistant to heat, sunlight, and dessication and can survive for decades. Anthrax usually occurs in those handling infected animals or their products, including hides, hair, wool, or flesh. Spores are introduced through a break in the skin, leading to a small raised area on the skin which ulcerates and turns black. (The name anthrax is derived from the Greek word for coal.) When untreated, the illness may be complicated by high fevers, swelling of the area around the ulcer, enlargement of the regional lymph nodes, infection of the bloodstream, and death. However, the cure rate is high when appropriate antibiotics are given. Rarely, inhalation of anthrax spores causes inhalational anthrax, known historically as Woolsorters' Disease, which progresses rapidly and is often fatal despite treatment. Inhalational anthrax begins with non-specific flu-like symptoms, including fever, malaise, fatigue, dry cough, and chest discomfort, followed by the abrupt onset of respiratory distress, cyanosis (purplish color), profuse sweating, confusion, and shock. The chief finding is hemorrhagic mediastinitis (bloody inflammation of the lymph nodes in the center of the chest). The chest film may show a widened mediastinum or effusions, but generally does not show infiltrates. Chest CT is often helpful in assessing the mediastinal lymph nodes, especially if plain chest films are non-diagnostic. The course is frequently complicated by hemorrhagic meningitis (blood in the spinal fluid). The diagnosis of an anthrax skin infection is generally made by culturing the skin lesion, though cultures are usually negative after antibiotics have been given. Immunohistochemical staining of tissue specimens obtained from the edge of the skin lesion may be helpful. The diagnosis of inhalational anthrax is generally confirmed by positive blood cultures. The microbiology laboratory should be alerted that anthrax is to be ruled out, because most Bacillus species found in blood cultures are contaminants. If blood cultures are negative, serum and other body fluids may be sent for PCR. A nasal swab for culture or direct fluorescent antigen may be positive shortly after exposure to anthrax, but may be negative by the time of clinical illness. Pending final culture results, initial therapy for inhalational anthrax should consist of cipro 400 mg every 12 hours or doxycycline 100 mg every 12 hours by vein, in combination with a second antibiotic. For children, the recommended dosages are cipro 5-7.5 mg/kg every 12 hours and doxycycline 2.5 mg/kg every 12 hours, up to the adult dosages. Data are limited, but other quinolones are likely to be equally effective. Options for the second antibiotic include rifampin, vancomycin, imipenem, chloramphenicol, penicillin and ampicillin, clindamycin, and clarithromycin (Biaxin), all of which have shown activity against the strains of anthrax recently isolated in the United States. After clinical improvement, treatment may be completed with either one or two drugs. Therapy should be continued for a total of 60-100 days. Penicillin should not be used alone for inhalational anthrax, even if the strain appears susceptible, because laboratory studies suggest the organism may become resistant during treatment. Steroids may be used as adjunct therapy in cases with extensive edema, respiratory compromise, or meningitis. Anthrax of the skin is usually treated with cipro or doxycycline alone. If the illness is complicated by extensive swelling or severe toxicity, a second antibiotic should be added, as for inhalational anthrax. Because of potential adverse effects of prolonged use of cipro or doxycycline in children and pregnant women, penicillin or amoxicillin may be substituted for cipro or doxycycyline once the strain has been shown to be susceptible to penicillin and the patient is clinically improving. In pregnant women, cipro is thought to be preferable to doxycycline, because the latter drug may be associated with an increased risk of bone and dental abnormalities in the developing fetus. Those exposed to anthrax spores should be promptly started on cipro 500 mg twice daily or doxycycline 100 mg twice daily by mouth, to be continued for 60-100 days. If the strain is found to be susceptible to penicillin, high-dose penicillin or amoxicillin may be given. Anthrax is not transmissible from person-to-person. In the hospital, standard barrier precautions should be adequate (i.e. masks are not necessary once the diagnosis is confirmed). Anthrax vaccine may be effective, but supplies are limited and have been reserved for military personnel and laboratory workers. A total of six doses over 18 months is recommended. For the most recent recommendations concerning management of anthrax exposure, go to Anthrax as a Biological Weapon, 2002. For the most recent recommendations on the use of anthrax vaccine, see Notice to Readers: Use of Anthrax Vaccine in Response to Terrorism: Supplemental Recommendations of the Advisory Committee on Immunization Practices on the CDC website. From the World Health Organization (WHO) Anthrax (overview for travelers) Anthrax fact sheet Guidance on anthrax: frequently asked questions Guidelines for the Surveillance and Control of Anthrax in Humans and Animals From the Centers for Disease Control (CDC) Frequently asked questions Technical information Anthrax fact sheet Anthrax Emerging Infectious Diseases: Bioterrorism-Related Anthrax (special issue) Notice to Readers: Use of Anthrax Vaccine in Response to Terrorism: Supplemental Recommendations of the Advisory Committee on Immunization Practices Update: Investigation of Bioterrorism-Related Anthrax and Interim Guidelines for Clinical Evaluation of Persons with Possible Anthrax Update: Investigation of Bioterrorism-Related Anthrax and Adverse Events from Antimicrobial Prophylaxis Notice to Readers: Updated Recommendations for Antimicrobial Prophylaxis Among Asymptomatic Pregnant Women After Exposure to Bacillus anthracis Notice to Readers: Update: Interim Recommendations for Antimicrobial Prophylaxis for Children and Breastfeeding Mothers and Treatment of Children with Anthrax Notice to Readers: Additional Options for Preventive Treatment for Persons Exposed to Inhalational Anthrax Public health updates Anthrax of the Gastrointestinal Tract From the U.K. Health Protection Agency Anthrax - general information Questions commonly asked by health care providers about anthrax (PDF) Interim Guidelines for Action in the Event of a Deliberate Release (PDF) Anthrax photos From the Journal of the American Medical Association (JAMA) Anthrax as a Biological Weapon Anthrax as a Biological Weapon, 2002 From the New England Journal of Medicine (NEJM) Anthrax (review article) Recognition and Management of Anthrax - An Update (PDF), Morton S. Swartz Images in Clinical Medicine - Cutaneous Anthrax Infection (PDF) From Emerging Infectious Diseases Bioterrorism-Related Inhalation Anthrax: The First 10 Cases Reported in the United States, J. Jernigan Clinical Issues in the Prophylaxis, Diagnosis, and Treatment of Anthrax, D. Bell Anthrax of the Gastrointestinal Tract, T. Sirisanthana and A. E. Brown From the United States Department of Defense Anthrax Information Resources Medical Aspects of Chemical and Biological Warfare (PDF) Brucellosis Brucellosis is an infection of domestic and wild animals that may be transmitted to humans through direct animal contact or by consumption of unpasteurized dairy products from infected animals. Cattle, goats, and sheep are the most common source of infection, though pigs, buffalo, camels, and yaks may be important in certain areas. The incubation period usually ranges from one to four weeks. Symptoms may include fever, malaise, depression, loss of appetite, headache, muscle aches, and back pain. Complications may include arthritis, hepatitis, endocarditis, and meningitis. Infection may be short-lived or last for years. Diagnosis is made by blood cultures or serologic tests. Treatment options include doxycycline plus rifampin, doxycycline plus streptomycin, and rifampin plus a quinolone. No vaccine is available at this time. Prevention depends upon avoidance of unpasteurized dairy products and limiting contact with potentially infected animals and their bodily fluids. From the World Health Organization Brucellosis fact sheet BruNet From the Centers for Disease Control Brucellosis: frequently asked questions Brucellosis: technical information Brucellosis From the U.K. Health Protection Agency Brucellosis From Emerging Infectious Diseases Brucellosis: an Overview by M.J. Corbel From the Lancet Infectious Diseases The new global map of human brucellosis by Georgios Pappas et al. (Lancet Infect Dis 2006; 6:91-99) Botulism Botulinum toxin, which is produced by a bacterium known as Clostridium botulinum, is the most poisonous substance known to man. In animals, only 0.001 microgram per kilogram of body weight results in a fatality rate of 50%. Recent concern has focused on the possible use of botulinum toxin as a biological weapon, either by contamination of water supplies or aerosol dissemination. However, botulinum toxin is readily inactivated by sunlight, heat, and chlorine, which would limit though not eliminate its potential as a biological weapon. Most cases of botulism are caused by ingestion of pre-formed toxin in contaminated foods. In newborns, botulism may develop from multiplication of Clostridium botulinum organisms in the immature gut. Rarely, botulinum toxin enters the body through an open wound. Though this does not happen in nature, the toxin can be aerosolized and absorbed from the respiratory tract. Regardless of how the toxin enters the body, the resulting clinical syndrome is essentially the same. Botulinum toxin acts by blocking acetylcholine release at peripheral cholinergic synapses, chiefly at the neuromuscular junction. Clinically, botulism presents as a symmetric, descending flaccid paralysis that begins in the head and face and spreads downward. Initial findings may include drooping eyelids, blurred vision, double vision, dry mouth, slurred speech and difficulty swallowing, followed by loss of muscle tone, generalized weakness, and loss of the gag reflex, which may require intubation to protect the airway. Patients may appear lethargic, but mentation is otherwise normal. Sensory abnormalities do not occur. There is no fever. The cerebrospinal fluid is normal. Electromyography may be helpful in distinguishing botulism from other flaccid paralyses, Diagnosis is usually made on the basis of symptoms and physical examination. The diagnosis should be confirmed by assaying blood, stool, gastric aspirate, and possibly other body fluids for botulinum toxin, which is performed at a small number of reference laboratories. Samples must be obtained before the patient has received antitoxin. The treatment of botulism is to give antitoxin, which is available from the health department, and to support aggressively, preferably in an ICU. The licensed antitoxin contains antibodies against three of the seven types of botulinum toxin (A, B, and E), which cause most cases of human disease. An investigational antitoxin which is active against all seven types is held by the US Army. Because botulinum antitoxin is derived from horses, hypersensitivity reactions, including hives, serum sickness, and anaphylaxis, occur in a significant minority of patients. Those who have been exposed to botulinum toxin but remain asymptomatic are generally observed closely and not given antitoxin, due to short supplies of antitoxin and the frequency of hypersensitivity reactions. An investigational vaccine containing botulinum toxoid (analogous to tetanus toxoid) has been used for more than thirty years to immunize laboratory workers, but is not routinely given to the general population due to the rarity of botulism and the scarcity of the vaccine. The vaccine is not effective when given after exposure. From the Centers for Disease Control Botulism: General Information Botulism: Technical Information Botulism Handbook (PDF) Botulism From the Public Health Laboratory Service (U.K.) Botulism - general information Interim Guidelines for Action in the Event of a Deliberate Release (PDF) From the Journal of the American Medical Association (JAMA) Botulism as a Biological Weapon (PDF) From the United States Department of Defense Medical Aspects of Chemical and Biological Warfare (PDF) Chagas Disease Chagas disease is a parasitic infection caused by an organism known as Trypanosoma cruzi. The disease is transmitted by triatomine insects (reduviid bugs), which inhabit crevices in the walls and roofs of substandard housing in South and Central America. The triatomine insect lays its feces on human skin as it bites, usually at night. A person becomes infected when he or she unknowingly rubs the feces into the bite wound or any other open sore. The disease may also be transmitted by blood transfusions or by infected mothers passing it to their babies in the uterus or through breastfeeding, but these are much less common (see Risk for Transfusion-Transmitted Infectious Diseases in Central and South America, Emerging Infectious Diseases Vol. 4/No. 1 January-March 1998). The acute stage of the disease is seen most often in children. Symptoms may include fever, lymph node swelling, enlargement of the liver or spleen, and fatigue. Swelling around one eye (Romana's sign) may occur if insect feces are rubbed into the eye. Most people who are infected show no initial symptoms. However, ten to twenty years later, about one-third of those infected show evidence of irreversible damage to the heart, esophagus, or large intestine. Cardiac symptoms may include abnormal heart rhythms, heart failure, angina, left ventricular aneurysm, and cardiac arrest. Esophageal involvement may lead to difficulty swallowing and malnutrition. Intestinal involvement may cause constipation and abdominal distention. Most travelers are at extremely low risk for Chagas disease. However, those sleeping in poorly constructed houses, especially those made of mud, adobe, or thatch, may become infected and should use bed nets and insecticides to prevent transmission. There is no vaccine for Chagas disease. Early infections may be treated with nifurtimox or benznidazole, but there is no effective antibiotic for late-stage disease at this time. From the World Health Organization Chagas disease: the disease Chagas disease: burdens and trends Chagas disease: recent data for the Southern Cone Countries Chagas disease: geographical distribution From the Centers for Disease Control (CDC) Chagas' Disease Fact Sheet on Chagas Disease American Trypanosomiasis (life cycle, geographic distribution, clinical features, diagnosis, treatment) From the Pan American Health Organization Chagas Disease (American Trypanosomiasis) From Health Canada American Trypanosomiasis or Chagas Disease From TDR Chagas disease update (latest news) Chickenpox (varicella) Chickenpox is a common, highly contagious viral infection caused by an organism known as varicella-zoster virus. The incubation period ranges from one to three weeks. Symptoms include fever, malaise, body aches, sore throat, headache, and a distinctive rash consisting of tiny blisters (vesicles) all over the body. Cases of chickenpox remain infectious until the skin lesions crust over, usually five to seven days after they appear. Complications may include pneumonia, hepatitis, encephalitis, and bacterial skin infections. Chickenpox may be treated with acyclovir, famcyclovir, or valacyclovir, but mild cases in children usually require no treatment except analgesics, antihistamines, and baths for relief of pain and itching. Varicella vaccine (Varivax; Merck and Co., Inc) (PDF) consists of a weakened strain of varicella-zoster virus. In adults, a complete series consists of two doses separated by one to two months. In children, a single dose is sufficient. The vaccine is recommended for international travelers who are not immune to chickenpox. Many people who believe they never had chickenpox in fact have antibodies to chickenpox in their blood, probably as a result of a childhood case that was so mild that it was never diagnosed. Checking for chickenpox antibodies before receiving the vaccine is therefore a reasonable option for travelers with no history of the disease. The most common adverse reaction to the vaccine is pain or swelling at the injection site. Occasionally, recipients of the vaccine develop a mild varicella-like illness. Rarely, mild cases of shingles (zoster) have been reported. Anyone with a history of allergy to gelatin, neomycin, or a prior dose of varicella vaccine should not receive the vaccine. Because the vaccine contains live virus, it should not be given to pregnant women or those who are immunosuppressed due to malignancies, immune deficiency disease (including HIV), or immunosuppressive medications. Because of the association between aspirin use and Reye syndrome following chickenpox, aspirin and other salicylates should be avoided for 6 weeks after receiving varicella vaccine. From the World Health Organization (WHO) Varicella vaccines (WHO position paper) Varicella vaccine (background) From the Centers for Disease Control (CDC) Varicella (Chickenpox) Varicella Varicella fact sheet Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices(PDF) Prevention of varicella: updated recommendations of the Advisory Committee on Immunization Practices From Health Canada Update on Varicella Statement on Recommended Use of Varicella Virus Vaccine Chikungunya Fever Chikungunya fever is a viral infection transmitted by mosquito bites. Symptoms include fever, joint pains, muscle aches, headache, and rash. The disease is almost never fatal, but may be complicated by protracted fatigue, malaise, and joint pains, chiefly involving the wrists, ankles, and fingers. Laboratory abnormalities may include low platelet counts and elevated liver enzymes. The diagnosis is confirmed by blood tests, usually an immunocapture ELISA, which show the presence of antibodies against chikungunya virus. Rarely, the infection is complicated by meningoencephalitis, which is usually seen in newborns and those with pre-existing medical conditions. There is no vaccine at present. Travelers may reduce their risk by keeping themselves covered, applying insect repellent, and taking other measures to prevent mosquito bites. Because of the risk of mother-to-child transmission, pregnant women need to take special care to protect themselves from mosquito bites. From the World Health Organization (WHO) Chikungunya Fever From the Centers for Disease Control (CDC) Chikungunya Fever Fact Sheet Update: Chikungunya Fever Diagnosed Among International Travelers --- United States, 2006 Cholera Cholera is an intestinal infection caused by a bacterium known as Vibrio cholerae. Cholera is acquired through ingestion of contaminated food or water. It is rarely spread from person-to-person. The incubation period ranges from less than one to five days. In most cases, infection with Vibrio cholerae causes either no symptoms or mild diarrhea. Some, however, develop profuse watery diarrhea, usually with vomiting, leading to profound dehydration, which may be fatal. The cornerstone of treatment is rehydration, usually with oral rehydration solution. Severe cases may require intravenous fluids. Antibiotics are also given, usually tetracycline or doxycycline, though quinolone antibiotics such as ciprofloxacin and levofloxacin are also effective. A recent study in Bangladesh showed that a single 1-gram dose of azithromycin (Zithromax) was significantly more effective than a single 1-gram dose of ciprofloxacin (see the New England Journal of Medicine). Cholera is rare in travelers, including those visiting countries where cholera outbreaks are occurring. In previous years, cholera vaccination was required for entry into many countries, but is no longer required of any traveler. As of August 2000, the only cholera vaccine approved for use in the United States was no longer being manufactured or sold. (See the Centers for Disease Control for details.) The vaccine had not been generally recommended because it reduces the rate of infections by no more than 50%, is effective for no more than 3-6 months, and frequently causes pain at the injection site. Three oral vaccines have been developed, including Orochol (Mutacol) and Dukoral. Mutacol and Dukoral are licensed in Canada and Australia and Dukoral is licensed in the European Union, but none of the oral cholera vaccines have been approved in the United States. The vaccines are generally safe, but protection has not been shown to last for more than six months. According to Health Canada and the National Travel Health Network and Centre (U.K.), oral cholera vaccines are not recommended for most travelers, but may be considered for those at higher than average risk, such as health professionals in endemic areas, aid workers in refugee camps, and those traveling to remote areas where cholera epidemics are occurring and there is limited access to medical care. See the review in the Weekly Epidemiological Record (PDF) for detailed information regarding the new vaccines. Cholera is best prevented by careful selection of food and beverages, as described elsewhere. Breast-feeding appears to be protective against cholera. From the World Health Organization (WHO) Cholera Cholera: Basic Facts for Travelers Cholera Fact Sheet Some frequently asked questions about cholera Cholera Vaccines (PDF) (2001) Cholera 1999 (PDF) (includes review of cholera vaccines) Cholera 2000 (PDF) (includes vaccine update) Cholera 2001 (PDF) (includes vaccine update) From the Centers for Disease Control (CDC) Cholera Frequently Asked Questions about Cholera Technical Information on Cholera Recommendations of the Advisory Committee on Immunization Practices: Cholera Vaccine (published in 1988 - gives useful information on older vaccines) From the National Travel Health Network and Centre (U.K.) A review of oral cholera vaccines: use in clinical practice Cholera vaccine From the Pan American Health Organization Cholera in the Americas From Health Canada Oral Cholera Vaccination From the Reviews in Medical Microbiology S. Kabir. Cholera vaccines: the current status and problems. Reviews in Medical Microbiology 2005, 16: 101-116. Coccidioidomycosis From the Centers for Disease Control (CDC) Coccidioidomycosis Technical information on coccidioidomycosis From Dr. Fungus Coccidioidomycosis Crimean-Congo Hemorrhagic Fever Crimean-Congo hemorrhagic fever is a viral infection that usually involves livestock, especially cattle, sheep, and goats, as well as certain birds, notably ostriches. Humans may acquire the disease by tick bites, by direct contact with infected animals or their tissues, or by exposure to an infected person. Most cases are reported in people who work with livestock, such as ranchers, shepherds, butchers, slaughterhouse workers, and veterinarians. Peak incidence occurs in the spring and fall. The incubation period is usually one to three days after a tick bite and five to six days after direct animal exposure. Initial symptoms may include fever, muscle aches, backache, joint pains, headaches, dizziness, and light sensitivity, as well as nausea, vomiting, diarrhea and abdominal pain. Signs of excessive bleeding (hemorrhage) may be observed. In severely ill patients, complications may include liver, kidney and respiratory failure. Neurologic symptoms may include mood swings, confusion, agitation, and obtundation. There is evidence that the antiviral drug ribavirin may be effective. No vaccine is currently available. The best means of prevention is to follow tick precautions and to wear gloves and protective garments when handling animal tissues or caring for infected patients. Strict barrier precautions are essential when patients with suspected Crimean-Congo hemorrhagic fever are admitted to the hospital. From the World Health Organization (WHO) Crimean-Congo haemorrhagic fever fact sheet Crimean-Congo haemorrhagic fever (CCHF) - Geographic distribution Dengue fever Dengue fever is a viral infection that typically causes flu-like symptoms, including fever, muscle aches, joint pains, headaches, nausea, and vomiting, often followed by a rash. Most cases are mild and resolve uneventfully in a few days. However, dengue sometimes causes excessive bleeding (dengue hemorrhagic fever) or a dangerous fall in blood pressure (dengue shock syndrome) that may be fatal. The available evidence indicates that that children under age 15 experiencing a second dengue infection are at greatest risk for severe disease, which implies that adult travelers who have never been exposed to dengue are unlikely to develop these complications. Dengue is transmitted by Aedes mosquitoes, which bite preferentially during the daytime, especially in the morning and late afternoon (in contrast to Anopheles mosquitoes, the vectors of malaria, which are most active after sundown). Aedes mosquitoes are usually found close to human habitations, often indoors. They breed primarily in man-made water containers, such as jars, barrels, cans, cisterns, metal drums, plastic containers, and discarded tires. As a result, dengue is especially common in densely populated, urban environments, though it occurs in rural areas as well. The disease has been spreading in recent years, due in part to increasing urbanization, and is now endemic in more than one hundred tropical and subtropical countries. A recent study of dengue in returned travelers showed that the risk peaked at different times of the year in different regions: in June and September for Southeast Asia, in October for south central Asia, in March for South America, and in August and October for the Caribbean (see Seasonality, Annual Trends, and Characteristics of Dengue among Ill Returned Travelers, 1997-2006, Emerging Infectious Diseases, 14 (7) 2008, pp. 1081-1088). In the year 2005, a total of 96 cases of dengue were identified in travelers from the United States, mostly after visits to Mexico, Central America, and the Caribbean. A smaller number occurred after travel to Asia. There is no treatment for dengue fever except to take analgesics such as acetaminophen (Tylenol) and drink plenty of fluids. Severe cases may require hospitalization for intravenous fluids and supportive care. There is no vaccine at this time. The cornerstone of prevention is insect protection measures, described elsewhere. From the World Health Organization (WHO) DengueNet Dengue fever: the disease Dengue fever fact sheet Dengue fever burdens and trends Dengue fever geographical distribution Dengue. Weekly Epidemiological Record, 19 June 1998 (PDF) Dengue fever in Southeast Asia Update on dengue in the Western Pacific region - August 2001 Dengue in the WHO Western Pacific Region. Weekly Epidemiological Record, 4 September 1998 (PDF) Dengue and Dengue Haemorrhagic Fever in the Americas 1996. Weekly Epidemiological Record, 25 April 1997 (PDF) Dengue Prevention and Control. Weekly Epidemiological Record, 8 February 2002 (PDF) Dengue haemorrhagic fever: diagnosis, treatment, prevention and control. 2nd edition. Geneva : World Health Organization. 1997 "Global situation of dengue and dengue haemorrhagic fever, and its emergence in the Americas" (PDF). (1) World Health Statistics Quarterly, 50: 1997. From the Centers for Disease Control (CDC) Dengue Fever Dengue Fever Home Page Dengue Fever Fact Sheet Dengue and Dengue Hemorrhagic Fever: Questions and Answers Dengue and Dengue Hemorrhagic Fever: Information for Health Care Practitioners Travel-Associated Dengue --- United States, 2005 Imported Dengue --- United States, 1999 and 2000 From the Pan American Health Organization Dengue in the Americas From Health Canada International reports on dengue and dengue hemorrhagic fever Dengue fever From the Health Protection Agency (U.K.) Dengue fever - worldwide update From the Hawaii Department of Health Dengue Fever Information Center From TDR Dengue update (latest news) Diphtheria Diphtheria is an infection of the respiratory tract or skin caused by a bacterium known as Corynebacterium diphtheriae. The organism is transmitted from person to person through exposure to respiratory secretions or fluid from infected skin. The incubation period ranges from one to six days. In respiratory tract infections, the main symptoms are sore throat and fever, sometimes accompanied by nausea, vomiting, headache, and swelling of the neck. A distinctive grayish membrane, which is particularly characteristic of diphtheria, may develop in the throat or other areas of the oral cavity and may obstruct breathing. Other complications may include nerve weakness (neuropathy), inflammation of the heart (myocarditis), or pneumonia. Prompt administration of diphtheria antitoxin (serum containing diphtheria antibodies) is essential. At the present time, there is no preparation of diphtheria antitoxin licensed in the United States. However, diphtheria antitoxin produced by Pasteur Merieux, Lyon, France is licensed in Europe and is available in the United States through an Investigational New Drug (IND) protocol through the CDC. Physicians treating a case of suspected diphtheria can telephone the diphtheria duty officer at (404) 639-8255 from 8 a.m. to 4:30 p.m. Eastern time or (404) 639-2889 at all other times. Penicillin or erythromycin should also be given, though not as a substitute for antitoxin. Cases of respiratory tract diphtheria must be strictly isolated. Contacts should be given a booster dose of diphtheria vaccine. Contacts who may not have immunity to diphtheria should also be given a course of prophylactic antibiotics. Diphtheria of the skin is typically an indolent, chronic infection, seen most often in the tropics, but observed elsewhere in settings of poverty and poor hygiene. All skin infections should be treated with antibiotics, but some longstanding cases may not require antitoxin. Combined tetanus-diphtheria vaccine is recommended for all adults who have not been immunized within the past 10 years. Diphtheria vaccine consists of diphtheria toxin that has been inactivated by formaldehyde and adsorbed onto aluminum salts to increase its effectiveness. The vaccine is routinely given, in combination with tetanus and pertussis vaccines, to all children at ages 2 months, 4 months, 6 months, 15-18 months, and 4-6 years, followed by a tetanus-diphtheria booster every 10 years thereafter. An accelerated immunization schedule is recommended for children who have not completed their immunizations and who will be traveling to developing countries, especially the newly independent states of the former Soviet Union, where a massive diphtheria epidemic is in progress. Unvaccinated persons more than seven years of age should receive three doses of adult tetanus-diphtheria vaccine. The first two doses should be separated by 4-8 weeks, and the third dose should be given 6-12 months after the second. Reactions to tetanus-diphtheria vaccine may include fever or discomfort and swelling at the injection site. Severe allergic reactions, which occur rarely, are a contraindication to further doses of the vaccine. High-risk countries for diphtheria include Algeria, Egypt, most countries in sub-Saharan Africa, Brazil, Dominican Republic, Ecuador, Haiti, Afghanistan, Bangladesh, Myanmar, Cambodia, China, India, Indonesia, Iran, Iraq, Laos, Mongolia, Nepal, Pakistan, Philippines, Syria, Thailand, Turkey, Vietnam, Yemen, Albania, and all countries of the former Soviet Union. From the World Health Organization (WHO) Diphtheria Diphtheria toxoid vaccine From the Centers for Disease Control (CDC) Travelers' Health Information on Diphtheria, Tetanus, and Pertussis Technical Information on Diphtheria Diphtheria Ebola hemorrhagic fever Ebola hemorrhagic fever is a life-threatening viral infection that is generally acquired by direct contact with the blood or body fluids of infected persons. Outbreaks have been reported from Uganda, Gabon, the Sudan, and the Republic of the Congo. A single case has also been reported from Cote d'Ivoire. Major outbreaks have been reported among gorillas in the Republic of the Congo, which may be a source of human infections. A related virus, called Ebola-Reston, has been isolated from monkeys imported from the Philippines to the United States, but has not been shown to cause clinical illness in humans, i.e. blood tests show that humans have been infected with Ebola-Reston, but they don't become sick. The incubation period of Ebola hemorrhagic fever ranges from 2 to 21 days, most often 4 to 10 days. Initial symptoms include fever, muscle aches, headaches, fatigue, and sore throat, followed by rash, vomiting and diarrhea. Complications include hemorrhage, dehydration, dangerously low blood pressure, liver impairment, and kidney failure. There is no treatment except for aggressive supportive measures, such as intravenous fluids, transfusions, etc. Suspected cases should be strictly isolated, including both respiratory and body fluid precautions. Except for health care personnel and relief workers, travelers are generally at low risk for infection, because close contact with those who are infected or their remains is usually necessary for transmission. From the World Health Organization (WHO) Ebola haemorrhagic fever - fact sheet revised in May 2004 Image of the Ebola Virus Ebola: The Virus and the Disease. A special supplement of The Journal of Infectious Diseases (Vol. 79, Supplement 1, February 1999) sponsored by WHO and the Centers for Disease Control and Prevention. Outbreak of Ebola hemorrhagic fever, Uganda, August 2000 - January 2001. Weekly Epidemiological Record 9 Feb 2001, vol. 76, pp. 41-48. From the Centers for Disease Control (CDC) Fact Sheet on Ebola Virus Viral Hemorrhagic Fevers Reemergence of Ebola Virus in Africa (A. Sanchez et al., Emerging Infectious Diseases, July-September 1995) Viral Hemorrhagic Fevers From Health Canada Ebola Haemorrhagic Fever From "Science" Ebola Outbreak Killed 5000 Gorillas Foot-and-mouth disease Foot-and-mouth disease is a highly contagious viral disease which affects cloven-hoofed animals, including cattle, pigs, sheep, goats, and deer. Though rarely fatal, it is extremely debilitating and may cause devastating losses in milk and meat production. Although humans are frequently exposed to foot-and-mouth disease through contact with livestock, human illness is extremely rare. The symptoms in humans, when they occur, are typically mild and may include fever, sore throat, and uncomfortable tingling blisters in the mouth and on the hands and feet. Recovery usually occurs within a week. Although foot-and-mouth disease poses no significant threat to humans, people may spread the disease if their clothing, shoes, or personal effects become contaminated. Travelers may find that, in a country where an outbreak of foot-and-mouth disease is occurring, travel is restricted to prevent further spread of the disease. For recommendations to prevent travelers from spreading the disease to animals in the United States, please see the Centers for Disease Control. From Eurosurveillance Animal foot and mouth disease outbreak does not threaten public health From Health Canada Animal Foot-and-Mouth Disease in the UK and Other Affected Countries: Not a Public Health Threat to Travellers Animal Foot-and-Mouth Disease in the UK and Other Affected Countries: Not a Public Health Threat to Travellers - Update* From the United States Department of Agriculture Foot-and-Mouth Disease Foot-and-Mouth Disease Questions and Answers More Detailed Information on USDA Restrictions on Products from Countries with Foot-and-Mouth Disease From the U.S. State Department Foot-and-Mouth Disease From the U.K. Department for Environment, Food and Rural Affairs About Foot-and-Mouth Disease From Humanitarian Resource Institute Foot-and-mouth disease reference library Hand, foot, and mouth disease From the Centers for Disease Control Hand, foot, and mouth disease Hantavirus From the Centers for Disease Control (CDC) All About Hantavirus Hantavirus Pulmonary Syndrome --- United States: Updated Recommendations for Risk Reduction Hepatitis A Hepatitis A is a viral infection of the liver found throughout the world, though the incidence is relatively low in the United States and other developed countries. After travelers' diarrhea, hepatitis A is the most common travel-related infection. The disease may be acquired by direct contact with infected persons; from contaminated water or ice, including shellfish harvested from sewage-contaminated water; or from foods contaminated by infected food handlers. Symptoms may include fever, malaise, jaundice, nausea, vomiting, and abdominal pain. Most cases resolve without complications, though hepatitis A occasionally causes severe liver damage. The disease is diagnosed by the presence of hepatitis A IgM antibodies in the blood. There is no treatment. Hepatitis A vaccine is recommended for all travelers to developing countries. Two vaccines are currently available in the United States: VAQTA (Merck and Co., Inc.) (PDF) and Havrix (GlaxoSmithKline) (PDF). Both are well-tolerated. Side-effects are generally mild and may include soreness at the injection site, headaches, and malaise. More serious events, including severe allergic reactions, Guillain-Barre syndrome, brachial plexus neuropathy, transverse myelitis, encephalopathy, and erythema multiforme, have been reported after hepatitis A vaccine, generally in adults also receiving other vaccines. The relationship between hepatitis A and these occurrences remains unclear. No serious adverse events have ever been definitively attributed to hepatitis A vaccine. Hepatitis A vaccine should not be given to anyone with a history of hypersensitivity to alum, which is a component of both vaccines. Also, those allergic to 2-phenoxyethanol should not be given HAVRIX. The safety of hepatitis A vaccine in pregnancy has not been determined. However, since the vaccine is made from inactivated virus, the risk is thought to be very low. For both vaccines, the recommended adult dosage is 1.0 ml by intramuscular injection into the deltoid muscle. The dosage should be reduced to 0.5 ml for those between 2 and 18 years of age. The vaccine should be given at least two weeks prior to departure in order for antibody titers to rise to sufficient levels to confer immunity. A booster dose should be given 6-12 months later to provide long-term immunity. Two doses of hepatitis A vaccine appear to confer protection for at least ten years. Recent evidence indicates that the duration of protection after two doses is probably 20 years or greater (see NATHNAC). VAQTA is approved for those greater than 12 months of age. Havrix is approved for children greater than 2 years of age. Older adults, immunocompromised persons, and those with chronic liver disease or other chronic medical conditions who have less than two weeks before departure should receive a single intramuscular dose of immune globulin (0.02 mL/kg) at a separate anatomic injection site in addition to the initial dose of vaccine. Travelers who are less than one year of age or allergic to a vaccine component should receive a single intramuscular dose of immune globulin (0.02 mL/kg), which provides effective protection for up to three months, in the place of vaccine. If the travel period is expected to be greater than two months, the dosage of immune globulin should be 0.06 mL/kg; administration must be repeated if the travel period is greater than five months. Measles, mumps, rubella, and varicella vaccines should not be given for 3-11 months after immune globulin, depending on the quantity administered (see Spacing of Immunobiologics on the CDC website). A combined hepatitis A and hepatitis B vaccine (Twinrix; GlaxoSmithKline) (PDF) is now available. A full series consists of three intramuscular doses given at times 0, 1, and 6 months, as for hepatitis B vaccine. An accelerated dosing schedule of 0, 7, 21-30 days and a month 12 booster dose was recently approved by the FDA. Adverse reactions appear comparable to those reported for previously licensed hepatitis A and B vaccines. In the United States, the vaccine is approved for those 18 years or older. In other parts of the world, including Canada and Europe, a pediatric formulation (Twinrix Junior) is available. For travelers who require immunization against both types of hepatitis, Twinrix will reduce the number of total injections from five to three, though it will not change the minimum time necessary for immunization. The amount of hepatitis A antigen in Twinrix is half that in single antigen hepatitis A vaccine (Havrix). Hepatitis A antibody levels are high after Twinrix, but it is unknown whether or not the lower dose will affect the duration of immunity. On December 10, 2001, the U.S. Food and Drug Administration recalled certain lots of VAQTA, listed on its website, because some prefilled syringes were found not to contain enough antigen. Those who received the adult formulation after May 29, 2001, or the pediatric formulation after August 9, 1999, may be affected. See the Centers for Disease Control for details. In Europe, all stocks of VAQTA have been withdrawn from the market pending further inquiry. See Eurosurveillance, CDR Weekly, and the U.K. Department of Health for further information. Those who received vaccine which has been recalled may not be adequately protected against hepatitis A and should either be revaccinated or tested for immunity before departure. In Canada, two additonal hepatitis A vaccines have been licensed. See Health Canada for further information. From the World Health Organization Hepatitis A (brief introduction) Hepatitis A (detailed introduction) Hepatitis A vaccine Safety of hepatitis A vaccine Global distribution of hepatitis A, B and C, 2001. Weekly Epidemiological Record, 8 February 2002 (PDF) From the Centers for Disease Control (CDC) Hepatitis, Viral, Type A Viral Hepatitis A Fact Sheet Viral Hepatitis A Frequently Asked Questions Hepatitis A Vaccine Information Statement (PDF) Twinrix: Combined Hepatitis A and Hepatitis B Vaccine FDA Approval for a Combined Hepatitis A and B Vaccine Chiefly for physicians: Update: Prevention of Hepatitis A After Exposure to Hepatitis A Virus and in International Travelers. Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP) Licensure of Inactivated Hepatitis A Vaccine and Recommendations for Use Among International Travelers (PDF) (MMWR) Prevention of Hepatitis A Through Active or Passive Immunization: Recommendations of the Advisory Committee on Immunization Practices (PDF) (latest recommendations for hepatitis A vaccine, not specifically for travelers) (MMWR) Sources of Immune Globulin for Intramuscular Administration (IMIG) From Health Canada Hepatitis A Statement on Hepatitis A Vaccines for Travellers Supplementary Statement on Hepatitis A Vaccine Statement on Combination Vaccines against Hepatitis A and Hepatitis B From the National Travel Health Network and Centre (U.K.) Hepatitis A From the U.K. Health Protection Agency Hepatitis A Guidelines for the control of hepatitis A infection Hepatitis B Hepatitis B is a viral infection of the liver, found world-wide, with highest incidence in Africa, East Asia, the Pacific basin, the Amazon basin, the Asian republics of the former Soviet Union, the Caribbean, and the Middle East (except Israel) (see Geographic Pattern of Hepatitis B Prevalence, 1997). The virus may be transmitted by several routes: (1) from mother to child during pregnancy; (2) through exposure to infected blood, either through blood transfusions, contaminated needles, open skin wounds, or other means; (3) by sexual contact. The incubation period ranges from . Symptoms may include fever, malaise, jaundice, nausea, vomiting, and abdominal pain. Most cases resolve slowly but uneventfully. However, a small percentage leads to chronic liver damage (chronic hepatitis or cirrhosis) and sometimes liver cancer. Most travelers are at low risk for hepatitis B. The vaccine is recommended only for long-term (more than 6 months) travelers who expect to live in rural areas or have close physical contact with the local population in areas where hepatitis B is prevalent. Additionally, the vaccine is recommended for anyone who anticipates sexual contact with the local inhabitants or a possible need for medical, dental, or other treatments while abroad, especially if transfusions or injections may be expected. All health care providers, whether or not they travel, should be immunized against hepatitis B. Hepatitis B vaccine is safe and highly effective. Two hepatitis B vaccines are currently licensed in the United States: Recombivax HB (Merck and Co., Inc.) (PDF) and Engerix-B (GlaxoSmithKline) (PDF). A full series consists of three intramuscular doses (1.0 ml for adults, 0.5 ml for children from birth to age 19). The second and third doses are given one and six months, respectively, after the first. (Engerix-B has also been licensed for a four-dose series given at 0, 1, 2, and 12 months.) For travelers at high risk for hepatitis B who are going to endemic areas on short notice, hepatitis B vaccine may be given at 0, 7, and 21–28 days, although this schedule has not been approved by FDA. Side-effects of hepatitis B vaccine, if they occur, are typically mild and may include discomfort at the infection site and low-grade fever. Rarely, severe allergic reactions (anaphylaxis) occur, which contraindicates further doses. Other events have been reported after hepatitis B vaccine (multiple sclerosis, optic neuritis, rheumatoid arthritis, diabetes mellitus, hair loss), but the relationship between the vaccine and these occurrences remains unclear. Preliminary evidence linking hepatitis B vaccine to leukemia has not been supported by other studies (see the World Health Organization). On the basis of limited data, there is no apparent risk to the fetus when the vaccine is given during pregnancy. A combined hepatitis A and hepatitis B vaccine (Twinrix; GlaxoSmithKline) (PDF) is now available. A full series consists of three intramuscular doses given at times 0, 1, and 6 months, as for hepatitis B vaccine. An accelerated dosing schedule of 0, 7, 21-30 days and a month 12 booster dose was recently approved by the FDA. Adverse reactions appear comparable to those reported for previously licensed hepatitis A and B vaccines. In the United States, the vaccine is approved for those 18 years or older. In other parts of the world, including Canada and Europe, a pediatric formulation (Twinrix Junior) is available. For travelers who require immunization against both types of hepatitis, Twinrix will reduce the number of total injections from five to three, though it will not change the minimum time necessary for immunization. The amount of hepatitis A antigen in Twinrix is half that in single antigen hepatitis A vaccine (Engerix). Hepatitis A antibody levels are high after Twinrix, but it is unknown whether or not the lower dose will affect the duration of immunity. (Two doses of single antigen hepatitis A vaccine confer protection for at least ten years). From the World Health Organization (WHO) Hepatitis B (brief introduction) Hepatitis B (detailed introduction) Hepatitis B fact sheet Hepatitis B vaccine Hepatitis B: transmission and vaccination Global distribution of hepatitis A, B and C, 2001. Weekly Epidemiological Record, 8 February 2002 (PDF) Geographic prevalence of hepatitis B, 1997 From the Centers for Disease Control (CDC) Hepatitis, Viral, Type B Hepatitis B Fact Sheet Hepatitis B Frequently Asked Questions Hepatitis B Vaccine Fact Sheet Hepatitis B Vaccine Frequently Asked Questions Hepatitis B Vaccine Information (PDF) Twinrix: Combined Hepatitis A and Hepatitis B Vaccine FDA Approval for a Combined Hepatitis A and B Vaccine Chiefly for physicians: Availability of Hepatitis B Vaccine That Does Not Contain Thimerosal as a Preservative Update: Expanded Availability of Thimerosal Preservative-Free Hepatitis B Vaccine Hepatitis B Virus: A Comprehensive Strategy for Eliminating Transmission in the United States Through Universal Childhood Vaccination:Recommendations of the Immunization Practices Advisory Committee (ACIP) (general immunization recommendations, not specifically for travelers) Update: Recommendations to Prevent Hepatitis B Virus Transmission: United States (general immunization recommendations, not specifically for travelers) From Health Canada Statement on Combination Vaccines against Hepatitis A and Hepatitis B From the U.K. Health Protection Agency Hepatitis B Hepatitis C Hepatitis C is a viral infection of the liver that has a propensity to cause chronic liver damage and may sometimes lead to liver cancer. Up to 3% of the world's population is infected with hepatitis C. The virus is usually transmitted by exposure to infected blood (i.e. by transfusions or by contaminated needles). Less frequently, the disease is acquired through sexual intercourse or passed from mother to infant at birth. The infection is not usually transmitted from person to person in the absence of sexual contact or needle sharing. The symptoms of hepatitis C may include fever, jaundice, nausea, vomiting, abdominal pain, and malaise, but most cases are asymptomatic. The disease, when chronic, may be treated with interferon and ribavirin. Most travelers are at low risk for hepatitis C. There is no vaccine at this time. Prevention depends upon avoiding needle sharing and unprotected sex, as well as shunning procedures such as tattooing, body piercing, and scarification that may lead to hepatitis C if equipment is not properly sterilized. In countries where blood is not screened for hepatitis C, all possible efforts should be made to avoid receiving transfusions. From the World Health Organization (WHO) Hepatitis C fact sheet Hepatitis C (brief introduction) Global distribution of hepatitis A, B and C, 2001. Weekly Epidemiological Record, Vol. 77, 6, 2002 Hepatitis C: global prevalence (update) (PDF). Weekly Epidemiological Record, Vol. 75, 3, 2000 Global surveillance and control of hepatitis C (PDF). Journal of Viral Hepatitis, Vol. 6, 1999 Hepatitis C: global prevalence (PDF). Weekly Epidemiological Record, Vol. 72, 46, 1997 Hepatitis C (PDF). Weekly Epidemiological Record, Vol. 72, 10, 1997 From the Centers for Disease Control (CDC) Hepatitis, Viral, Type C Hepatitis C Frequently Asked Questions Hepatitis C Prevention Recommendations for Prevention and Control of Hepatitis C Virus (HCV) Infection and HCV-Related Chronic Disease (PDF) (most complete summary) From the UK Health Protection Agency Hepatitis C Hepatitis E Hepatitis E is a viral infection of the liver that occurs in epidemics as well as sporadically in many countries. The disease is not reported from the United States, except for rare reports among travelers. The virus is usually transmitted by contaminated drinking water. Epidemics often occur after heavy rainfall. The incubation period ranges from 2-9 weeks. Symptoms may include fever, jaundice, malaise, nausea, vomiting, and abdominal pain. The illness usually resolves without complications in 1-6 weeks. However, for unknown reasons, pregnant women who contract hepatitis E are at high risk for developing fulminant hepatitis, resulting in a 15-20% fatality rate. Hepatitis E infection can be diagnosed by measuring antibodies to hepatitis E virus in the blood. There is no treatment. Immune globulin prepared in countries where the disease is not endemic, such as the United States, does not appear to be protective. An experimental vaccine has been developed, but is not yet generally available. The best means of prevention is close adherence to food and water precautions, as outlined elsewhere. From the World Health Organization Hepatitis E (brief introduction) Hepatitis E (detailed introduction) Hepatitis E Fact Sheet From the Centers for Disease Control Hepatitis, Viral, Type E Hepatitis E Virus Slideset Histoplasmosis From the Centers for Disease Control (CDC) Histoplasmosis Frequently asked questions about histoplasmosis Technical information about histoplasmosis Histoplasmosis: protecting workers at risk Avian influenza ("bird flu") Outbreaks of highly pathogenic H5N1 avian influenza ("bird flu") began on poultry farms in Southeast Asia in December 2003. The outbreak was initially controlled by mass culling of millions of birds, but recurred in July 2004 and has spread steadily since then. Since July 2004, cases have been reported from poultry farms in Viet Nam, Thailand, China, Cambodia, Indonesia, Malaysia, Myanmar, Turkey, Russia, Albania, Czech Republic, Hungary, Poland, Romania, the Ukraine, France, Germany, Denmark, Israel, Jordan, Iraq, Iran, Kuwait, India, Bangladesh, Pakistan, Bhutan, Kazakhstan, Azerbaijan, Afghanistan, Egypt, Nigeria, Niger, Benin, Togo, Ghana, Sudan, Burkina Faso, Cote d'Ivoire, Djibouti, and Cameroon. Cases have also been reported in migratory birds in the United Kingdom, Austria, Sweden, Switzerland, Greece, Italy, Poland, Hungary, Croatia, Bulgaria, Georgia, Czech Republic, Serbia and Montenegro, Bosnia and Herzegovina, Slovakia, Slovenia, Spain, Mongolia, and Hong Kong (significant because migratory birds are thought to be involved in spreading the disease from one country to another). A total of 499 human cases have been identified to date, more than half of them fatal: 166 from Indonesia, 119 from Viet Nam, 108 from Egypt, 39 from China, 25 from Thailand, 12 from Turkey, 10 from Cambodia, 8 from Azerbaijan, 3 each from Pakistan and Iraq, 2 from Laos, and one each from Bangladesh, Myanmar, Nigeria and Djibouti. Of these, 73 cases were reported in the year 2009. At the present time, most of the new cases are being reported from Egypt, Indonesia, Viet Nam, and China. Most cases have occurred in those who had direct contact with live, infected poultry, or, in a much smaller number of cases, sustained, intimate contact with family members suffering from the disease. However, in one quarter or more of cases, the source of exposure is unclear. Unlike human influenza, the greatest mortality is seen in young people (those between the ages of 10 and 49). The incubation period of avian influenza is usually 2-8 days, but may range up to 17 days. The illness usually begins with typical flu-like symptoms: high fevers, chills, body aches, dry cough. The infection may also begin with diarrhea, vomiting, or abdominal pains. Runny nose and sore throat are usually not part of the symptom complex. In severe cases, the infection progresses rapidly to pneumonia and respiratory failure, which are the most common causes of death. The U.S. Food and Drug Administration recently approved two new tests to diagnose H5N1 infections in humans: the Human Influenza Virus Real-Time RT-PCR Detection and Characterization Panel (see the FDA website) and a rapid test called the AVantage A/H5N1 Flu Test (see the FDA website). There are no proven therapies for H5N1 infections. There are limited data that some of the newer antiviral agents, such as oseltamivir (Tamiflu) and zanamivir (Relenza) (PDF), may be active against H5N1 influenza viruses in the test tube. Tamiflu-resistant strains have been isolated from patients in Viet Nam and Egypt, but most strains remain susceptible (see the New England Journal of Medicine and the World Health Organization). When used for avian influenza, it may be appropriate to give Tamiflu in higher doses and for a longer period of time than when used for human influenza (consider a regimen of 150 mg twice daily for 10-14 days). Limited data suggest that Tamiflu is most effective when given early in the illness (see Roche Pharmaceuticals. A vaccine for avian influenza was recently approved by the U.S. Food and Drug Administration (FDA), but produces adequate antibody levels in fewer than half of recipients and is not commercially available. The vaccine is being stockpiled by the U.S. government in the event of a public health emergency. See the FDA website for further information. The vaccines for human influenza do not protect against avian influenza. At present, the Centers for Disease Control and the World Health Organization do not recommend any travel restrictions for any country currently experiencing outbreaks of avian influenza. However, those traveling to these countries should avoid contact with live poultry, including visits to poultry farms and open markets with live birds, and should not touch any surfaces that may be contaminated with feces from poultry or other animals. Infected poultry are known to shed large amounts of virus in their droppings. The virus may survive for more than a month in bird droppings in cold weather and for nearly a week even in summer. Also, travelers should make sure all poultry and egg products are thoroughly cooked. Lastly, careful and frequent handwashing is strongly encouraged. Anyone who develops fever and flu-like symptoms after travel to a country with avian influenza should seek immediate medical attention. The reason why public health authorities are alarmed about avian influenza is that, although these viruses pose little risk to the human population at present, they might develop the ability to infect humans in the future, perhaps by acquiring genes from human influenza viruses. Since humans do not have immunity to avian influenza viruses, this could lead to a massive worldwide pandemic. For an excellent summary of the world situation as of the end of 2006, go to Eurosurveillance. For further information on avian influenza, go to the World Health Organization, the OIE, the Centers for Disease Control, and the New England Journal of Medicine. Also see the special issue of Science (April 21, 2006). For a map showing the areas involved by the current outbreak, go to the European Union website. There are a number of other strains of avian influenza (e.g. H7N2, H7N3, H7N7) that pose little risk to humans. Cases are almost entirely limited to those who have had direct contract with infected poultry or their droppings. Symptoms are typically mild: either conjunctitis ("pink-eye") or a flu-like illness. For a review of low pathogenicity avian influenza, go to Eurosurveillance. Influenza An outbreak caused by a novel strain of H1N1 influenza, commonly called "swine flu", began in Mexico in March 2009 and spread rapidly to many other countries. The virus contains a unique combination of swine, avian, and human influenza gene segments that had not been previously observed. Initial reports from Mexico indicated a high fatality rate in previously healthy young adults and older children, raising concerns that a worldwide pandemic might occur, similar to 1918. However, subsequent data from Mexico, as well as experience from other countries, indicated the H1N1 strain from 2009 is not nearly as lethal as some people initially feared. Preliminary data indicate that up to one-third of those greater than 60 years of age have antibodies against the novel H1N1 virus, whereas protective antibodies are found much less frequently in children and younger adults (see MMWR). This is consistent with the clinical experience so far, which indicates that the most severe cases are occurring in those younger than age 60. The World Health Organization does not recommend any travel restrictions at this time. To protect yourself from H1N1 influenza, wash your hands regularly and avoid close contact with anyone who is coughing or sneezing. Routine use of face masks is not recommended. The symptoms of H1N1 influenza include fever, cough, sore throat, body aches, headache, chills and fatigue, similar to seasonal influenza. Any traveler who develops flu-like symptoms after travel to a country which has reported H1N1 influenza should immediately seek medical attention. Empiric treatment with oseltamivir (Tamiflu) and zanamivir (Relenza) should be considered for suspected cases. A small number of Tamiflu-resistant isolates have been described, but these strains have retained sensitivity to Relenza. The virus is uniformly resistant to amantadine and rimantadine. Vaccination against novel H1N1 influenza is recommended for everyone, except those allergic to the vaccine or one of its components. For further information on novel H1N1 influenza (swine flu), go to the World Health Organization and the Centers for Disease Control. The following is the latest update from the World Health Organization: As of 12 July, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18337deaths. WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information. Situation update: Worldwide, overall pandemic influenza activity remains low. The most active areas of pandemic influenza virus transmission currently are in parts of South Asia, West Africa, and Central America. In the temperate zone of the southern hemisphere, pandemic and seasonal influenza activity has remained low during the first half of the southern hemisphere winter, except in South Africa, where increased detections of primarily seasonal influenza viruses (type B and H3N2) were reported during late June and early July 2010. Seasonal influenza H3N2 viruses continue to circulate at varying levels across parts of the Americas, Africa, and Southeast Asia. Increased seasonal influenza activity continues to be observed in several countries of Central America. To date, most countries of the temperate zone of the southern hemisphere, with the exception of South Africa, have reported low overall levels of respiratory disease activity and low to sporadic levels of pandemic and seasonal influenza virus circulation during the first half of the southern hemisphere winter season. Pandemic influenza viruses have been detected only sporadically or at low levels in most of these countries. As reported last week, South Africa began observing a sharp increase in the proportion of sentinel respiratory samples testing positive for influenza virus (primarily seasonal influenza B and H3N2) during late June 2010, reaching a peak of ~50% detection rate during the first week of July 2010, and falling to ~40% during the second week of July 2010. In Chile (as of late June 2010) and Argentina (as of early July 2010), the most recent available data show that influenza activity remains sporadic in Argentina and low in Chile (~5% respiratory samples tested positive for influenza, 84% of which were pandemic virus with small numbers of seasonal influenza H3N2 and type B detected as well). In both Chile and Argentina, RSV has been the predominant circulating respiratory virus since mid-April 2010. In Australia, as of the last week of June 2010, overall rates of ILI remained low and below levels observed during the same period in past three winter seasons. Although a small cluster of pandemic influenza cases, including a few hospitalized cases, were recently detected in the Northern Territory of Australia, pandemic and seasonal influenza virus detections remain otherwise sporadic, albeit slightly increased during late June and early July 2010. Similarly, in New Zealand, rates of ILI have remained low and below the seasonal baseline, with only sporadic detections of pandemic and seasonal H3N2 viruses through the first week of July 2010. In both Australia and New Zealand, current levels of ILI are similar to those observed during the same period in 2008, when the influenza season was noted to have arrived and peaked late in winter. In Asia, overall pandemic influenza activity remains low to sporadic, except in parts of southern and western India, Malaysia, and Singapore. As reported last week, in India, transmission of pandemic influenza virus remains active but stable in the southern state of Kerala. The extent of illness in the community is currently being assessed and monitored by the Government of India. Similar numbers of new cases, including small numbers of fatal cases, have been reported on a weekly basis since transmission first increased during mid-June 2010. Recent, small increases in pandemic influenza virus circulation have also been observed since mid-June 2010 in other southern and western states of India, particularly in the western state of Maharashtra. In Singapore, levels of ARI increased during the first two weeks of July 2010; however, the intensity of pandemic influenza virus transmission has declined during June and July 2010 after peaking in May 2010. The proportion of patients with ILI testing positive for pandemic influenza virus in Singapore remained stable (14-16%) during first two weeks of July 2010. In addition, substantial co-circulation of seasonal influenza H3N2 viruses (with pandemic H1N1 virus) was detected in Singapore throughout May and June 2010. In Malaysia, numbers of new cases of pandemic influenza continued to decline; overall pandemic influenza activity fell substantially in June and early July 2010 after peaking during mid-April to mid-May 2010. Low levels of seasonal influenza type B viruses (and to much lesser extent pandemic influenza virus) continue to circulate across northern and southern China as levels of ILI remain stable and near seasonal levels seen in the same period in recent years. Low levels of pandemic and seasonal influenza (H3N2 and type B) viruses also continued to circulate in Hong Kong SAR (China), Chinese Taipei, and parts of Thailand. In the tropical regions of the Americas, overall pandemic and seasonal influenza activity remained low, except in parts of Central and South America, where there has been recent active co-circulation of pandemic and seasonal influenza H3N2 viruses. The majority of recent active transmission of pandemic influenza virus has been reported in Colombia, Costa Rica, and to a lesser extent in Cuba. In Colombia, although low level circulation of pandemic influenza viruses has persisted throughout the first half 2010, a second period of active transmission began in mid-May 2010, peaked in June 2010, has now largely subsided during the second of week of July 2010. Similarly, in Costa Rica, low level circulation of pandemic virus has persisted throughout 2010, however, there has been a recent resurgence in active transmission (though less intense than the initial 2009 wave) of pandemic influenza virus during June 2010. As reported previously, in Panama, a sharp increase in the circulation influenza A viruses (particularly H3N2, but also small numbers of pandemic H1N1) was reported over the month of June 2010; a high intensity of respiratory diseases and a moderate impact on healthcare services continued to be reported during the second week of July 2010. In Nicaragua, recent active transmission of seasonal influenza H3N2 viruses, which began during late May 2010 and peaked during mid June 2010, appears to have largely subsided during recent weeks. Many countries in the region continue to report ongoing co-circulation of other respiratory viruses, most notably RSV. In sub-Saharan Africa, the current situation is largely unchanged since the last update. Pandemic and seasonal influenza activity continues to be observed in several countries. Ghana, in West Africa, continued to have a sustained resurgence in circulation of pandemic influenza virus during June 2010, more than several months after the first period of pandemic activity peaked (early April 2010). Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, particularly in Cameroon, where an increase in influenza type B virus circulation was observed during June 2010. Small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern and southern Africa; the most recent detections have been reported in Kenya and South Africa. Overall, in the temperate regions of the northern hemisphere (North America and Europe), pandemic and seasonal influenza viruses have been detected only sporadically or at very low levels during the past month. Influenza background information: Influenza is a viral infection characterized by fever, chills, malaise, headaches, body aches, and cough, sometimes complicated by pneumonia, which may be life-threatening. All age groups may be affected, but severe illness is more common in the elderly and in those with chronic illnesses such as asthma, diabetes, kidney failure, and heart disease. Influenza occurs in annual epidemics from November to March in the temperate regions of the Northern Hemisphere and from April to September in the temperate regions of the Southern Hemisphere. However, travelers in large groups, especially those on cruise ships, may be at risk year-round, due to exposure to influenza viruses carried by persons from other parts of the world. Influenza is reported sporadically throughout the year in the tropics. Because influenza may cause significant distress during foreign travel, because medical care may be difficult to obtain while abroad, and because the symptoms of influenza, which are non-specific, may be confused with those of other illnesses, influenza vaccine should be seriously considered for all international travelers at risk, i.e. those traveling to the Northern Hemisphere between November and March, those traveling to the Southern Hemisphere between April and September, and those traveling on cruise ships or to the tropics at any time. Influenza vaccine is strongly recommended for all those over age 50 and for those with chronic medical conditions such as diabetes, emphysema, asthma, or heart disease. The vaccine should be given at least two weeks before departure. Twice each year, before influenza season in the Northern and Southern Hemispheres, the World Health Organization makes recommendations for vaccine composition, depending upon which strains appear most likely to cause outbreaks. If influenza vaccine for the Southern Hemisphere is not available, the vaccine for the preceding influenza season in the Northern Hemisphere, if obtainable, is the recommended alternative. For the year 2009, the vaccine recommended for the Southern Hemisphere is the same as that which had been given in the Northern Hemisphere for the winter of 2008-2009. The most frequent side-effect of influenza vaccine is mild discomfort at the injection site. Fever, malaise, and body aches may occur, but are typically mild. Severe reactions, generally allergic, are rare. Because the viruses in the vaccine are inactivated, influenza vaccine cannot cause influenza. Influenza vaccine should not be given to anyone allergic to eggs or in the first trimester of pregnancy. A new nasal-spray flu vaccine was licensed in the United States in 2003. Unlike the injectable flu vaccine, it contains live, weakened flu virus. It includes the same strains of influenza as the injectable vaccine and appears to have comparable efficacy. In the United States, the nasal-spray vaccine is only approved for use in healthy people between the ages of 5 and 49. The first-line drugs to treat influenza have been oseltamivir (Tamiflu) and zanamivir (Relenza) (PDF). However, in December 2008, the Centers for Disease Control reported that almost all the strains of influenza A (H1N1) isolated to date that winter were resistant to oseltamivir (Tamiflu). In March 2009, the World Health Organization reported high prevalence of oseltamivir resistance among H1N1 strains from Canada, Hong Kong SAR, Japan, the Republic of Korea, the United States, France, Germany, Ireland, Italy, Sweden and the United Kingdom. The CDC has therefore advised that, when influenza A (H1N1) virus infection or exposure is suspected, zanamivir or a combination of oseltamivir and rimantadine (Flumadine) should be given, rather than oseltamivir alone (see the Centers for Disease Control. Oseltamivir is available as 75-mg capsules, given twice daily by mouth for five days. The most common side-effects are nausea and vomiting, which are generally mild. Zanamivir is a dry powder prepared as an oral inhaler, given two inhalations twice daily for five days. Zanamivir may cause an exacerbation of asthma or chronic obstructive lung disease; it should be given with caution to persons suffering from those diseases. The usual dosage of rimantadine is 100 mg twice daily. Rimantadine should be avoided in those with a history of seizures, though the risk appears small. If rimantadine is not available, an older drug called amantadine is an acceptable alternative. Rimantadine and amantadine are only effective against influenza A viruses, as opposed to oseltamivir and zanamivir, which have been active against both influenza A and B. From the World Health Organization Recommended viruses for influenza vaccines for use in the 2010-2011 northern hemisphere influenza season FluNet (Global Influenza Surveillance Network) Influenza fact sheet Influenza vaccine Influenza vaccines - WHO position paper (PDF) Influenza vaccine manufacturers Influenza in the world 1 October 2000 - 30 September 2001 (PDF) From the Centers for Disease Control (CDC) Influenza Home Page Influenza Influenza: The Disease Influenza: Prevention and Control Influenza: Questions and Answers Influenza: Vaccine Information Antiviral Drugs for Influenza Influenza B Virus Outbreak on a Cruise Ship --- Northern Europe, 2000 Chiefly for physicians: Update: influenza activity -- United States and worldwide, 2006/2007 season, and composition of the 2007/2008 influenza vaccineMMWR August 10, 2007/Vol. 56(31): 789-94 Prevention and Control of Influenza: Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2007MMWR July 29, 2007/Vol. 56:1-54 Neuraminidase Inhibitors for Treatment of Influenza A and B Infections (MMWR December 17, 1999/Vol. 48/RR-14 Influenza vaccines(PDF) From Health Canada Influenza and Travel: Cruise Ships and Land-based ToursSupplementary Statement for the 2002-2003 Influenza Season:Update on Oculo-Respiratory Syndrome in Association with Influenza Vaccination From the U.K. Health Protection Agency Influenza Frequently asked questions on flu Weekly reports for the influenza season 2003-2004 From Emerging Infectious Diseases Special Issue: Influenza Japanese Encephalitis Japanese encephalitis (JE) is the leading cause of viral encephalitis (brain infection) in Asia. The disease occurs chiefly in China, Korea, Southeast Asia and the Indian subcontinent (see map showing distribution of Japanese encephalitis in Asia). Japanese encephalitis is transmitted by Culex mosquitoes, which breed in ground pools, especially flooded rice fields, and bite primarily after dusk. The virus lives principally in domestic pigs and Ardeid (wading) birds. Transmission of Japanese encephalitis is therefore greatest in rural, agricultural areas where rice paddies and pig farming co-exist. The risk may be increased by heavy rainfall and irrigation. Most infections are asymptomatic. But encephalitis, when it occurs, is severe and frequently leads to death or permanent brain damage. The risk of Japanese encephalitis for most travelers appears to be very small. From 1992 to 2008, only four cases were reported in U.S. residents. All were Asian immigrants or family members who traveled to Asia to live or to visit friends or relatives and who had not been vaccinated against the disease (see MMWR). From 1973 to 1992, only 11 cases of Japanese encephalitis were reported in U.S. residents, five of whom were civilians. Japanese encephalitis vaccine is recommended for those who expect to spend a month or more in rural areas where Japanese encephalitis is reported and for short-term travelers who may spend substantial time outdoors or engage in extensive outdoor activities in rural or agricultural areas where the disease occurs, especially in the evening. For those age 17 or older, the recommended vaccine is IXIARO, which was approved by the U.S. Food and Drug Administration in March 2009. The vaccine consists of purified, inactivated JE virus proteins. The recommended dosage is 0.5 cc given intramuscularly, followed by a second dose 28 days later. The series should be completed at least one week before travel. The most common side effects are headaches, muscle aches, and pain and tenderness at the injection site. Safety has not been established in pregnant women, nursing mothers, or children under the age of 17. The duration of protection after immunization is not known. An older vaccine, called JE-VAX (Aventis Pasteur), is recommended for those younger than age 17 who need to be vaccinated. JE-VAX is administered as a series of three 1.0 ml injections given subcutaneously on days 0, 7, and 30. The dosage is reduced to 0.5 ml for those 1-2 years of age. (No data are available on children less than one year of age.) Immunization should be completed at least 10 days prior to departure. About 20% of those vaccinated with JE-VAX experience mild reactions, including discomfort at the injection site, headaches, muscle aches, rash, nausea, vomiting, chills, dizziness, and malaise. Approximately 0.6% of vaccinees develop severe allergic reactions, including hives, facial swelling (angioedema), respiratory distress, and anaphylaxis, which may occur as long as one week after vaccination. Erythema multiforme, erythema nodosum, and joint swelling have also been reported. These reactions are treated with epinephrine, antihistamines, and/or steroids. Reactions may occur after any of the three doses, even if previous doses were well-tolerated. Vaccinees should be observed for 30 minutes after immunization and should remain in areas with access to medical care for at least ten days after vaccination. Those with a past history of hives are more likely to be allergic to JE-VAX. No further vaccine should be given if an allergic reaction occurs. When the full series is completed, JE-VAX appears to reduce symptomatic infections by 80-90%. Protective levels of antibody persist for at least three years. The full duration of protection is unknown. There are no recommendations concerning booster doses, but they may be given after three years. No information is available on the safety of the vaccine in pregnant women or in children less than one year of age. Japanese encephalitis may cause fetal death in the first and second trimesters, so the risk of the vaccine must be balanced against the risk of illness in a pregnant woman traveling to an endemic area. A small study of children with altered immune function implied no increased risk from the vaccine in this population. Insect protection measures are essential in areas where Japanese encephalitis is known to occur. From the World Health Organization (WHO) Japanese encephalitis (background information and vaccine position paper) Safety of Japanese encephalitis vaccine Japanese encephalitis vaccines: WHO position paper (PDF) Japanese encephalitis: disease burden and vaccines Japanese encephalitis (background) From the Centers for Disease Control (CDC) Japanese encephalitis Japanese encephalitis fact sheet Japanese encephalitis frequently asked questions Inactivated Japanese Encephalitis Vaccine: Recommendations of the Advisory Committee on Immunization Practices (PDF) (most complete summary) From the National Travel Health Network and Centre (U.K.) Japanese encephalitis From the New England Journal of Medicine T.Solomon, "Control of Japanese Encephalitis — Within Our Grasp?" (NEJM 2006; 355:869-871) Lassa fever Lassa fever is a life-threatening viral infection that is generally acquired by contact with the excreta of infected rodents, but may also be transmitted person-to-person. Outbreaks have been reported from the Central African Republic, Liberia, Nigeria and Sierra Leone. Blood tests indicate that the disease probably occurs in Democratic Republic of the Congo, Guinea, Mali and Senegal as well. The incubation period ranges from 1-3 weeks. Initial symptoms may include fever, malaise, headache, cough, nausea, vomiting, diarrhea, and muscle aches. The presence of an extremely sore throat, with white patches on the tonsils, may help distinguish Lassa fever from other infectious diseases. In severe cases, Lassa fever may lead to dangerously low blood pressure, excessive bleeding, fluid around the lungs (pleural effusion), seizures, or inflammation of the brain (encephalopathy). The treatment is intravenous ribavirin, as well as aggressive supportive measures. In general, the risk to travelers is small. However, health care providers caring for patients with Lassa fever may be at risk and should follow appropriate measures, which include strict respiratory and body fluid precautions. From the World Health Organization (WHO) Lassa Fever Fact Sheet From the Centers for Disease Control (CDC) Viral Hemorrhagic Fevers Fact Sheet on Lassa Fever Legionnaires' Disease Legionnaires' disease is a bacterial infection which typically causes pneumonia but may also involve other organ systems. The disease is usually transmitted by airborne droplets from contaminated water sources, such as cooling towers, air conditioners, whirlpools, and showers. Cases may occur sporadically or in outbreaks linked to specific locations, such as hotels or other public facilities. Small outbreaks have been reported from cruise ships, sometimes associated with onboard whirlpool spas. Legionnaires' disease is not transmitted from person to person. The incubation period ranges from two to ten days. Symptoms may include fever, cough, chest pain, difficulty breathing, headache, muscle pains, and diarrhea. Numerous complications have been reported, including kidney failure, liver failure, respiratory failure, muscle inflammation (rhabdomyolysis), abnormal bleeding (disseminated intravascular coagulation), and death. Legionnaires' disease may be treated with either azithromycin or a quinolone antibiotic, such as ciprofloxacin or levofloxacin. There is no vaccine. The European Working Group on Legionella Infections monitors cases of Legionnaires' disease in returning travelers in order to identify hotels, resorts, and other accommodations where Legionella outbreaks may be occurring. From the European Working Group on Legionella Infections About Legionnaires' Disease Legionnaires' Disease and Travel Minimising the risk: information for hoteliers Information for tour operators From the World Health Organization (WHO) Legionellosis Legionnaires' Disease, Europe, 1999 Legionnaires' Disease in Europe 1998 Legionnaires' Disease in Europe 1997 From the Centers for Disease Control Legionnellosis Cruise-Ship--Associated Legionnaires Disease, November 2003--May 2004 Legionnellosis From the U.K. Health Protection Agency Legionnaires' Disease From Eurosurveillance Travel-Associated Legionnaires' Disease in Europe: 2005 Travel-Associated Legionnaires' Disease in Europe: 2003 Launch of new European guidelines for control and prevention of travel associated legionnaires' disease Leishmaniasis Leishmaniasis is a parasitic disease which occurs in three forms: (1) visceral disease, characterized by fever, weight loss, anemia, and enlargement of the liver and spleen developing over months to years; (2) cutaneous disease, manifested by skin ulcers on exposed parts of the body developing over weeks to months; and (3) mucocutaneous disease, characterized by disfiguring erosions of the mucous membranes of the nose, mouth, and throat. The disease is transmitted by sandflies, which are about one-third the size of mosquitoes. Sandflies breed in sites where its larvae will find warmth, moisture, and organic matter, such as leaf litter, loose earth, old tree bark, rubbish heaps, and crevices in human dwellings. Sandflies typically bite from dusk to dawn, but may bite during the daytime if disturbed. There is no vaccine at present. The key to prevention is insect protection measures, which are essentially the same as those outlined for mosquitoes, except that netting must be finer-mesh (at least 18 holes to the linear inch) since sandflies are smaller. Cases of cutaneous leishmaniasis were reported in October 2003 among U.S. military personnel serving in Iraq (especially in the urban and periurban areas of An Nasiriyah and Baghdad), Kuwait (near the Iraqi border), and Afghanistan. For further information, go to MMWR. From the World Health Organization Leishmaniasis fact sheet Leishmaniasis: the disease and its impact Leishmaniasis: geographical distribution Urbanization: an increasing risk factor for Leishmaniasis (PDF) New therapy for visceral leishmaniasis (PDF) Programme for surveillance and control of Leishmaniasis (PDF) Leishmaniasis: disease burden and vaccines From the Centers for Disease Control (CDC) Leishmaniasis Leishmaniasis Fact Sheet Leishmaniasis (life cycle, geographic distribution, clinical features, diagnosis) From Health Canada Leishmaniasis From TDR Leishmaniasis Leptospirosis Leptospirosis is a spirochetal infection transmitted to humans by exposure to water contaminated by the urine of infected animals. Outbreaks often occur at times of flooding, when sewage overflow may contaminate water sources. Those who work with animals, such as farmers, animal handlers, and slaughterhouse workers, and those work in sewers are at greatest risk. The disease has also been reported among travelers after swimming, wading, or rafting in contaminated lakes or rivers. The incubation period usually ranges from 5 to 14 days. Initial symptoms may include fever, chills, headache, muscle aches, conjunctivitis (pink eye), photophobia (light sensitivity), and rash. In most instances, the symptoms subside uneventfully in 4-7 days. However, in a minority of cases, the illness enters a second, more serious phase, characterized by worsening headaches, fevers, chills, and muscle pains. A rash is often observed. Complications may include meningitis, kidney failure, liver failure, and bleeding into the lungs or gastrointestinal tract. The second phase may be separated from the first by several days, during which time the patient appears relatively well. The disease is treated with either oral doxycycline or intravenous penicillin. Severely ill patients require admission to the hospital for intravenous fluids and aggressive supportive care. In general, most travelers are at low risk for leptospirosis. The risk may be minimized by avoiding exposure to bodies of fresh water that may be contaminated by animal urine. There is no vaccine. Those who are visiting an area where an outbreak is in progress may be given a prophylactic 200 mg dose of doxycycline, either once weekly or as a one-time dose. From the Centers for Disease Control Leptospirosis Leptospirosis Frequently Asked Questions Leptospirosis (overview) From the U.K. Health Protection Agency Leptospirosis From Queensland Health, Australia Leptospirosis Fact Sheet Lyme disease Lyme disease is a tick-borne illness caused by spiral-shaped bacteria belonging to the genus Borrelia. The disease occurs in the temperate regions of North America, Europe and Asia. Far more cases are reported from central and northern Europe, especially Austria and Slovenia, than the southern countries. In the United States, the illness is reported in the Northeast, Midwest, and Pacific coastal regions. Lyme disease is transmitted by small hard ticks of the Ixodes complex. The nymphal stage is responsible for most infections. Disease activity peaks in the late spring and summer. The incubation period usually ranges from one to two weeks, but is variable. An expanding red rash, often pale in the center (known as a bull's eye rash), is the most common initial manifestation but, in many cases, the rash is not present or is not observed because of its location. Flu-like symptoms are common, including fever, headache, joint pains, body aches, and malaise. Complications may include (1) arthritis, resulting in painful swelling of one or more joints, especially large joints such as the knee; (2) infection of the nervous system, leading to meningitis, encephalitis, or Bells palsy; (3) cardiac involvement, usually manifesting as heart block (slow heart rate). Early treatment of Lyme disease with an appropriate oral antibiotic, generally doxycycline or amoxicillin, usually but not always prevents these complications from occurring. Treatment of complications may require an intravenous antibiotic, usually ceftriaxone. A Lyme vaccine (LYMErix; GlaxoSmithKline) has been approved by the U.S. Food and Drug Administration, but is no longer being manufactured or sold. Even when available, Lymerix is not generally recommended for travelers because full immunization requires three doses over a one-year period, which is not practical for most trips, and because the vaccine may not be effective against the strains present in Europe and Asia. Tick precautions are strongly advised for travel to rural and forested areas in regions where Lyme disease is known to occur. From the World Health Organization (WHO) Adverse Events following Lyme Disease Vaccine From the Centers for Disease Control (CDC) Lyme Disease Lyme Disease: Introduction Lyme Disease: The Bacterium Lyme Disease: Natural History Lyme Disease: Diagnosis Lyme Disease: Epidemiology Lyme Disease: Prevention and Control Lyme Disease: Vaccine Recommendations Lyme Disease: Questions and Answers Recommendations for the Use of Lyme Disease Vaccine Recommendations of the Advisory Committee on Immunization Practices (ACIP) (comprehensive summary; chiefly for physicians) From Eurosurveillance Lyme borreliosis: Europe-wide coordinated surveillance and action needed? From Health Canada Statement on Immunization for Lyme Disease From the American College of Physicians Guidelines for Laboratory Evaluation in the Diagnosis of Lyme Disease Laboratory Evaluation in the Diagnosis of Lyme Disease Lymphatic Filariasis From the World Health Organization Lymphatic filariasis fact sheet Lymphatic filariasis - background Lymphatic filariasis burdens and trends Lymphatic filariasis geographical distribution Lymphatic filariasis (PDF) (Weekly Epidemiological Record; May 18, 2001) Lymphatic filariasis (PDF) (Weekly Epidemiological Record; April 19, 2002) The global alliance to eliminate lymphatic filariasis (home page) Lymphatic filariasis photo gallery From the Centers for Disease Control Lymphatic Filariasis Fact Sheet on Filariasis Filariasis (life cycle, geographic distribution, clinical features, diagnosis) From the Liverpool School of Tropical Medicine Filiariasis.net From TDR Lymphatic filariasis update Variant Creutzfeldt-Jakob disease and bovine spongiform encephalopathy ("mad cow disease") Variant Creutzfeldt-Jakob disease (CJD) is a degenerative neurologic disease acquired by eating beef from cows with a related illness known as bovine spongiform encephalopathy (BSE) ("mad cow disease"). The disorder was initially described in the United Kingdom. As of June 2005, there were 155 definite or probable cases of variant CJD reported from the United Kingdom, as well as a small number of cases from France, Italy, and the Republic of Ireland. "Mad cow disease" has also been identified in Austria, Belgium, Czech Republic, Denmark, Finland, Germany, Greece, Liechtenstein, Luxembourg, the Netherlands, Portugal, Slovak Republic, Slovenia, Spain, Switzerland, Israel, Japan, and the United States, but human cases have not been reported from these countries to date. Bovine spongiform encephalopathy appears to be caused by abnormal proteins called prions, which do not resemble bacteria, viruses, or other conventional causes of human and animal disease. The agent that causes BSE is transmitted when meat and bone meal feed prepared from the carcasses of infected animals is fed back to other cattle. (This practice has been banned within the European Union and many other countries). The infection is not transmitted directly from animal to animal within herds. A new case of BSE arising within a country is therefore much more significant than an imported case, because it implies that recycled ruminant protein is still being used within that country as animal feed, against all current recommendations. The agent that causes BSE is concentrated in nervous tissue, such as brain and spinal cord. Since this agent has never been found in skeletal muscle, which is the source of most quality meat, the current thinking is that most cases of variant CJD are caused by contamination of meat by nervous tissue during slaughter and processing. Careful slaughter practices can therefore markedly reduce the risk of acquiring variant CJD, even in a country where BSE is known to occur. The incubation period of variant CJD appears to be several years or longer. Initial symptoms may be psychiatric, similar to depression or (less often) psychosis. Patients may complain of unusual sensory symptoms, such as "stickiness" of the skin. Later symptoms include unsteady gait, involuntary movements, dementia, and mutism, progressing inevitably to death within 1-2 years. There is no treatment. Variant CJD can only be acquired by eating beef or beef products; i.e if you do not consume beef or beef products while visiting a country which has reported "mad cow disease", you cannot become infected. There is no evidence of any risk from pork, lamb, milk or milk products. The Centers for Disease Control does not advise against eating European beef, but suggests that travelers who wish to reduce their risk may either abstain from beef completely while in Europe or eat only solid pieces of muscle meat, such as steak, rather than products like sausage or chopped meat that might be contaminated during processing. Cooking, drying, or freezing does not inactivate the agent that causes new variant CJD or prevent its transmission. In December 2003, a single case of transfusion-acquired variant CJD was reported from the United Kingdom. Since the time of the transfusion, which took place in early 1996, a number of measures have been instituted to protect the blood supply, including depletion of white blood cells, which are thought to be a potential source of infection. Procedures for blood transfusions in the U.K. are currently under review. For further information, go to Eurosurveillance. From the World Health Organization (WHO) Understanding the BSE Threat Bovine Spongiform Encephalopathy (BSE) Variant Creutzfeldt-Jakob Disease Surveillance and Response From the Centers for Disease Control (CDC) Creutzfeldt-Jakob Disease (Variant) and Bovine Spongiform Encephalopathy (Prion Diseases) Risk for Travelers BSE (Bovine Spongiform Encephalopathy, or Mad Cow Disease) vCJD (Variant Creutzfeldt-Jakob Disease) From the Office International des Epizooties Number of reported cases of BSE worldwide From Emerging Infectious Diseases Bovine Spongiform Encephalopathy and Variant Creutzfeldt-Jakob Disease: Background, Evolution, and Current Concerns From Eurosurveillance Eurosurveillance Monthly: Special issue on BSE and CJD From Health Canada Mad Cow or Bovine Spongiform Encephalopathy (BSE) in Europe Travel in Europe and Mad Cow Disease Other sites UK Creutzfeldt-Jakob Disease Surveillance Unit Bovine Spongiform Encephalopathy (UK Ministry of Agriculture, Fisheries and Food) European and Allied Countries Collaborative Study Group of CJD British Medical Journal Collected Resources: New Variant Creutzfeldt-Jakob Disease/BSE/Mad Cow Disease ProMED-mail Malaria Malaria is a parasitic infection of red blood cells and the liver caused by any of four related species: Plasmodium falciparum, P. vivax, P. ovale, and P. malariae. Malaria is transmitted by female Anopheline mosquitoes, which typically bite between dusk and dawn. The chief symptoms are fever, sweats, chills, headache, body aches, and malaise, typically accompanied by anemia and enlargement of the spleen. Complications may include jaundice, low blood sugar, kidney failure, fluid in the lungs (pulmonary edema or ARDS), and circulatory collapse. Infections caused by P. falciparum are particularly dangerous because of a propensity for infected red blood cells to obstruct blood flow to the brain, causing seizures, impaired consciousness, and sometimes coma. (There is recent evidence that a fifth species, P. knowlesi, previous thought to cause malaria only in monkeys, may also cause malaria in humans, especially in southeast Asia. In March 2009, a case was reported in a U.S. traveler to the Philippines. See MMWR for further information.) It is essential for all travelers to take medication to prevent malaria when visiting any area where malaria occurs, especially sub-Saharan Africa, which accounts for a majority of cases of travel-related malaria. In the United States, most cases of malaria occur in travelers who did not take appropriate malaria prophylaxis. Malaria pills should be purchased before departure, since medications obtained in developing nations may be fake. For countries where chloroquine-resistant malaria occurs, which includes most countries with malaria, there is a choice of three medications: mefloquine (Lariam), atovaquone/proguanil (Malarone)(PDF), or doxycycline. Mefloquine is given once weekly in a dosage of 250 mg, starting one-to-two weeks before arrival and continuing through the trip and for four weeks after departure. Mefloquine may cause mild neuropsychiatric symptoms, including nausea, vomiting, dizziness, insomnia, and nightmares. Rarely, severe reactions occur, including depression, anxiety, psychosis, hallucinations, and seizures. Mefloquine should not be given to anyone with a history of seizures, psychiatric illness, cardiac conduction disorders, or allergy to quinine or quinidine, which are related medications. Mefloquine should be avoided in scuba divers, because of the potential for lowering the seizure threshold, which might complicate decompression illness. For further information, see the Lariam Medication Guide (PDF). For children, the dosage is 5 mg/kg weekly for those weighing less than 15 kg but more than 5 kg, 1/4 pill (62.5 mg) weekly for those weighing 15-19 kg, 1/2 pill (125 mg) weekly for those weighing 20-30 kg, and 3/4 pill (187.5 mg) weekly for those weighing 31-45 kg. Children weighing more than 45 kg should be given the adult dosage. Mefloquine may be given to pregnant women in the second and third trimesters, but should be avoided if possible in the first trimester and in infants under 3 months of age (5 kg). Malarone is a recently approved combination pill consisting of 250 mg of atovaquone and 100 mg of proguanil, taken once daily with food starting two days before arrival and continuing through the trip and for seven days after departure. Side-effects, which are typically mild, may include abdominal pain, nausea, vomiting, headache, diarrhea, or dizziness. Serious adverse reactions are rare. For children, the dosage is one-half pediatric Malarone pill (containing 62.5 mg of atovaquone and 25 mg of proguanil) each day for those weighing 5-8 kg, 3/4 pediatric pill each day for those weighing 8-10 kg, one pediatric pill daily for those weighing 10-20 kg, two pediatric pills daily for those weighing 20-30 kg, and three pediatric pills daily for those weighing 30-40 kg. Children weighing more than 40 kg (88 pounds) should be given the adult dosage. Malarone is not recommended for use in pregnant or lactating women, in children weighing less than 5 kg (11 pounds), or in those with renal insufficiency. Proguanil may enhance the anticoagulant effect of warfarin (Coumadin). Limited data indicate that the efficacy of the two drugs is about the same and that Malarone may be somewhat better tolerated than Lariam. Malarone is only given for seven days after leaving a malarious area, compared to four weeks for Lariam. However, since Lariam is only given once weekly, the total number of pills that must be taken is greater for Malarone. Some authorities recommend Malarone for shorter trips and reserve Lariam for longer journeys abroad. Others prefer Lariam because of its longer track record and reserve Malarone for those unable to tolerate Lariam. The chief point is that, with the exception of travel to certain areas in Thailand, either drug is entirely appropriate for any trip to any area where chloroquine-resistant malaria occurs, i.e. what's important is to take one of the approved drugs, not which drug is taken. Doxycycline is also effective, but may cause an exaggerated sunburn reaction, which limits its usefulness in the tropics. Sunscreen is essential. Doxycycline may cause inflammation of the esophagus when taken on an empty stomach, especially at bedtime, so it should always be taken with food and never before lying down. In women, doxycycline is a frequent cause of vaginal yeast infections; an antifungal medication should be included in the medical kit. The usual dosage of doxycycline is 100 mg daily starting one or two days before arrival in the malarious area and continuing through the trip and for four weeks after departure. For children greater than 12 years of age, the dosage is 2 mg/kg daily up to the adult dosage of 100 mg. Doxycycline should not be given to children less than 12 years old, pregnant or lactating women, or anyone with a history of tetracycline allergy. It should also be avoided in anyone taking hepatotoxic medications and anyone with a history of liver disease, lupus, or myasthenia gravis. Doxycycline may increase the plasma levels of cyclosporine and may enhance the anticoagulant effect of warfarin (Coumadin). Though not approved for this usage in the United States, several studies have shown that primaquine is highly effective in preventing malaria. It is available in tablets containing 5, 7.5, and 15 mg of primaquine base (15 mg base is equivalent to 26.3 mg primaquine phosphate). The usual adult dosage is two 15 mg pills starting one day before arrival in the malarious area and continuing through the trip and for seven days after departure. For children 4 years or older, the dosage is 0.5 mg base/kg body weight. Adverse reactions may include nausea, vomiting, and abdominal pain. Primaquine may cause hemolytic anemia in those with G6PD deficiency, so a blood test documenting normal G6PD levels must be obtained before starting primaquine. In those with normal G6PD levels, the main side-effect of primaquine is gastrointestinal disturbance, which can be minimized by taking the medication with food. The combination of chloroquine and proguanil is no longer recommended by the CDC for the prevention of chloroquine-resistant malaria, because it appears less effective than either Lariam, Malarone, or doxycycline. There are a small number of countries where chloroquine, which for many years was the first-line drug against malaria, is still reliably effective. The list includes the Dominican Republic, Haiti, Central America west of the Panama Canal Zone, Egypt, and most countries in the Middle East. For these countries, the recommended prophylaxis is chloroquine 500 mg weekly, starting one week before arrival in the malarious area and continuing through the trip and for four weeks after departure. For children, the dosage is 8.3 mg/kg weekly, up to the adult dosage of 500 mg. The side-effects of chloroquine, which are generally minor, may include gastrointestinal disturbances, headache, dizziness, blurred vision, and itching. Those who have trouble tolerating chloroquine may take it with food or may divide the dose in half and take it twice weekly. Chloroquine may cause exacerbations of psoriasis or myasthenia gravis. Chloroquine should be avoided in travelers with a history of seizures, retinal disease, liver disease, or known hypersensitivity to the drug. There is no evidence of harmful effects during pregnancy. Because of possible drug interactions, chloroquine should be avoided in those taking moxifloxacin (Avelox) (increased risk of ventricular arrhythmias), amiodarone (increased risk of ventricular arrhythmias), cyclosporine (increased risk of toxicity), digoxin (possibly increases digoxin levels), and mefloquine (increased risk of seizures). Those taking chloroquine for more than 6 years should undergo periodic eye examinations because of a small risk of retinal toxicity. None of the above regimens gives complete protection. Both during and after the trip, travelers should be alert to the symptoms of malaria, which may include fever, chills, headaches, muscle aches, weakness, vomiting, or diarrhea. Travelers who may not have access to medical care should bring along medications for emergency self-treatment should they develop symptoms suggestive of malaria and cannot obtain medical care within 24 hours. One option for emergency self-treatment is to take a combination of artemether and lumefantrine, marketed as Coartem in the United States and as Riamet in Europe. Each pill contains 20 mg of artemether and 120 mg of lumefantrine. A 3-day course is recommended: one pill twice daily for those weighing 5-14 kg, 2 pills twice daily for those weighing 15-24 kg, 3 pills twice daily for those weighing 25-34 kg, and 4 pills twice daily for those weighing 35 kg or greater. The second dose should be given 8 hours after the first. Riamet/Coartem should be taken with milk or a fat-containing food. In adults, the most common adverse reactions are headache, loss of appetite, dizziness, weakness, joint pain, and muscle pain. In children, the most common adverse reactions are fever, cough, vomiting, loss of appetite, and headache. Riamet/Coartem should not be given during the first trimester of pregnancy, to nursing mothers, or to children weighing less than 5 kg. (A related drug called artesunate recently became available in the United States for treatment of severe malaria in-hospital, but only through the CDC's Drug Service and Quarantine Stations. To obtain the medication, physicians should call 770-488-7788 M-F, 8am-4:30pm eastern time, or 770-488-7100 after hours). Increasing resistance to artemisinin and artemisinin-derivatives, including artemether, has been reported from parts of southeast Asia, including western Cambodia, the border regions of Thailand and Cambodia, border regions of Thailand and Myanmar, eastern Myanmar, and the Binh Phuc Province of Viet Nam (see the World Health Organization. Another option is to take Malarone in a dosage of four pills daily for three consecutive days, but Malarone should not be used for self-treatment if the traveler has been on Malarone prophylaxis. For children weighing 25-45 pounds, the dosage is one adult pill taken daily for three days. For those weighing 46-67 or 68-88 pounds, the dosage is 2 or 3 adult pills daily, respectively, for three days. A final option for self-treatment is to take quinine 650 mg three times daily and doxycycline 100 mg twice daily for one week. For pregnant women, the recommendation for emergency self-treatment is quinine 650 mg mg three times daily with clindamycin 450 mg three times daily for 5-7 days, though pregnant women should make all possible efforts to obtain medical care rather than self-medicating. Malaria prophylaxis should be resumed one week after the first treatment dose, unless quinine has been used for self-treatment and mefloquine for prophylaxis, in which case mefloquine should be resumed one week after the last dose of quinine. Every effort should be made to consult with a physician rather than relying upon self-medication. Travelers who will have access to medical care do not need to bring along medication for emergency self-treatment. The importance of insect protection measures cannot be overstated. These are reviewed elsewhere. From the World Health Organization Roll back malaria department What is malaria? Malaria in pregnancy Children and malaria Insecticide-treated mosquito nets Guidelines for the treatment of malaria Diagnosis and treatment Epidemics and emergencies Pregnant women and infants Global distribution of malaria (map) Roll Back Malaria Partnership Malaria (from "International Travel and Health") From the Centers for Disease Control Malaria risk map Malaria home page Malaria Drugs To Prevent Malaria Information for the Public: Prescription Drugs for Malaria Malaria Treatment Guidelines Malaria: Prescription Drugs, Provider Info Diseases: Malaria: Prevention, Pregnant Women, Public Info Information for Health Care Providers: Preventing Malaria in the Pregnant Woman Information for the Public: Preventing Malaria in Infants and Children Information for Health Care Providers: Preventing Malaria in Infants and Children Malaria Deaths Following Inappropriate Malaria Chemoprophylaxis ---United States, 2001 (MMWR) Availability and Use of Parenteral Quinidine Gluconate for Severe or Complicated Malaria (MMWR) From Health Canada Malaria Canadian Recommendations for the Prevention and Treatment of Malaria Among International Travellers (detailed information including insect protection measures, antibiotic prophylaxis, and risk by country) Medical Access to Quinine for Malaria Treatment From the U.K. Health Protection Agency Malaria Malaria treatment guidelines Malaria Imported into the UK, 2003: implications for those advising travellers An internet-based tool-kit for the initial investigation of cases of cryptic malaria Guidelines for malaria prevention in travellers from the United Kingdom in 2003 (PDF) Malaria prophylaxis for long-term travellers (PDF) Cryptic malaria cases in England - 2002 From the Pan American Health Organization Malaria From the U.S. Food and Drug Administration Medication Guide to Lariam (PDF) (for patients) From the National Institutes of Health Multilateral Initiative on Malaria From TDR Malaria update Other sites Malaria Foundation International Multilateral Initiative on Malaria Marburg Virus Marburg virus infections, which are closely related to Ebola virus infections, may be highly infectious and rapidly fatal. Health care workers are at particularly high risk. The disease was first identified in 1967 after laboratory workers in Marburg, Germany became ill after handling infected monkeys imported from Uganda. Since that time, sporadic cases have been reported from Zimbabwe, South Africa, Kenya, and Democratic Republic of the Congo. A major outbreak was reported from Angola in 2004. A small outbreak was reported from western Uganda in July 2007. Initial symptoms include fever, muscle aches, headaches, fatigue and conjunctivitis, followed by sore throat, vomiting, diarrhea, and rash. Complications may include excessive bleeding, dangerously low blood pressure, low platelets, liver impairment, and kidney failure. There is no treatment for Marburg fever except aggressive supportive measures, including intravenous fluids, transfusions as needed, etc. Suspected cases must be strictly isolated, including both respiratory and body fluid precautions. There is no vaccine for Marburg virus at present. From the World Health Organization (WHO) Marburg Haemorrhagic Fever From the Centers for Disease Control (CDC) Fact Sheet on Marburg Hemorrhagic Fever Viral Hemorrhagic Fevers Viral Hemorrhagic Fevers From the New England Journal of Medicine H. Feldmann, "Marburg Hemorrhagic Fever — The Forgotten Cousin Strikes" (NEJM 2006; 355:866-869) Measles (Rubeola) Measles is a highly contagious viral disease which has been largely controlled in the United States but which remains widespread in many other countries. The illness is characterized by fever, conjunctivitis, runny nose, cough, and rash, which begins on the face and spreads downward. Complications may include bacterial pneumonia or encephalitis (inflammation of the brain). Combined measles, mumps, and rubella vaccine, known as MMR, is recommended for all children in a two-dose schedule at ages 12-15 months and 4-6 years. Children older than 6 months but younger than 12 months of age who will be traveling to countries where measles occurs should be given a dose of monovalent measles vaccine before departure, to be followed by two doses of MMR after age 12 months. Adults born after January 1, 1957, who do not have two documented measles vaccinations should either be immunized against measles or tested for measles immunity by measuring antibody levels. This is particularly important for those born in the late 1950's and 1960's, many of whom remain susceptible to measles because the recommendation at the time they were growing up was to give only one dose of measles vaccine. Adults born before January 1, 1957, are presumed to be immune to measles due to early childhood exposure before measles vaccine became available. Adverse reactions following MMR vaccine may include fever, rash, lymph node enlargement (due to the rubella component), inflammation of the parotid gland (due to the mumps component), or joint pains (due to the rubella component). Allergic reactions may occur but are rarely severe. Because MMR vaccine contains live, weakened strains of all three viruses, it should not be given to pregnant women or severely immunosuppressed individuals. It should also not be given to anyone with a history of severe allergy to gelatin, neomycin, or a prior dose of MMR. Reports that measles vaccine may be linked to autism, inflammatory bowel disease, and other disorders have not been confirmed. Unfortunately, these fears, which are medically unfounded, may have led to a decrease in measles immunization in a number of countries, including the United Kingdom. From the World Health Organization (WHO) Measles Fact Sheet Measles Safety of MMR vaccine Global measles mortality reduction and regional elimination 2000-2001 - Part 1 (PDF) Global measles mortality reduction and regional elimination 2000-2001 - Part 2 (PDF) Global advisory committee on vaccine safety (PDF) From the Centers for Disease Control (CDC) Measles Measles From Health Canada Measles From the New England Journal of Medicine A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism. Kreesten Meldgaard Madsen, M.D. et al. Volume 347:1477-1482. From Pediatrics Measles-Mumps-Rubella Vaccine and Autistic Spectrum Disorder Melioidosis From the Centers for Disease Control (CDC) Melioidosis Meningococcal disease Meningococcal meningitis is a life-threatening infection of the fluid and tissues surrounding the brain, caused by a bacterium known as Neisseria meningitides. The infection is spread person-to-person by exposure to secretions from the nose or throat. In most countries, meningococcal meningitis occurs sporadically, with small outbreaks occurring in closed communities, such as dormitories or military barracks. However, certain countries in sub-Saharan Africa, known as the "meningitis belt," periodically experience major epidemics, especially in the dry season (December through June). The incubation period ranges from two to ten days. Most people who are infected show no symptoms, but some develop meningitis, marked by the abrupt onset of fever, headache, stiff neck, and lethargy, frequently with a rash. Meningococcal meningitis must be promptly treated with intravenous antibiotics, usually penicillin, ampicillin, or ceftriaxone. The fatality rate may approach 10%, despite appropriate therapy. Among survivors, long-term complications may include deafness, seizures, or mental impairment. Meningococcal meningitis is rare among travelers. Meningococcal vaccine is recommended chiefly for travel to countries in the African "meningitis belt" during the dry season (December through June), especially if prolonged contact with the local populace is likely. In addition, the vaccine is periodically recommended for other countries reporting meningitis outbreaks. Immunization is required for travel to Mecca during the Hajj. Meningococcal vaccine consists of purified polysaccharides from the bacterial capsule, rather than live or killed bacteria. The main side-effect is mild redness at the injection site. Fever is uncommon. Serious reactions are not reported. Protective antibodies develop 10-14 days after vaccination. There are two meningococcal vaccines currently licensed in the United States. A new quadrivalent conjugate vaccine called Menactra; Sanofi-Pasteur appears to provide longer-lasting protection than an older vaccine, called (Menomune - A/C/Y/W-135; Aventis Pasteur Inc.). Both vaccines confer protection against four groups of Neisseria meningitides (A, C, Y, and W-135) but not group B, which may also cause epidemics. If at continued risk, children previously vaccinated at ages 2 through 6 years should receive an additional dose of Menactra three years after their previous meningococcal vaccine and every five years thereafter. Persons previously vaccinated at ages 7 through 55 years should receive an additional dose of Menactra five years after their previous dose and every five years thereafter, if at continued risk. In countries other than the United States, polysaccharide vaccines limited to groups A and C (bivalent) are also available. Since an increase in the number of meningococcal infections caused by group W-135 has recently been reported (see World Health Organization), bivalent vaccines should not in general be used for international travel. A protein-polysaccharide conjugate vaccine against group C meningococci has recently become available in Canada and the United Kingdom. Unlike the older polysaccharide vaccines, the conjugate vaccine is effective in infants and young children. However, since most outbreaks in developing nations are caused by meningococci belonging to groups other than C, this vaccine is generally not adequate for international travel. Regardless of immunization status, anyone who potentially has had direct contact with the oral or nasal secretions of an infected person should be treated prophylactically with rifampin 600 mg twice daily for 48 hours, a single 500 mg dose of ciprofloxacin, or a single 250 mg intramuscular dose of ceftriaxone. Those treated should include household contacts and anyone who sat next to an infected person during an extended plane flight. Menomune is available in 10-dose and single-dose vials. The manufacturer recently received FDA approval to extend the use of the 10-dose vial, after reconstitution, from 10 to 35 days. From the World Health Organization (WHO) Meningococcal vaccines: polysaccharide and polysaccharide conjugate vaccines (WHO position paper) (PDF) Meningococcal meningitis fact sheet Meningococcal outbreaks (from the Disease Outbreak News) Number of cases and deaths of meningococcal disease reported to WHO: 1998; 1999; 2000 Epidemics of meningococcal disease, African meningitis belt, 2001 (PDF) Meningococcal vaccine Safety of meningococcal vaccine Meningitis in college students Group A and C meningococcal vaccines: WHO position paper (PDF) From the Centers for Disease Control (CDC) Meningococcal disease Frequently Asked Questions about Meningococcal Disease Technical Information on Meningococcal Disease Prevention and Control of Meningococcal Disease: Recommendations of the Advisory Committee on Immunization Practices (ACIP) Exposure to Patients With Meningococcal Disease on Aircrafts ---United States, 1999--2001 From Health Canada Meningitis International Reports of Meningitis Statement on Meningococcal Vaccination for Travellers Statement on Recommended Use of Meningococcal Vaccines From the National Travel Health Network and Centre (U.K.) Changes to Meningococcal Meningitis Recommendations for Travellers From the U.K. Department of Health Meningitis C vaccine From Immunization Action Coalition Meningococcal information Mumps From the World Health Organization (WHO) Mumps Mumps vaccine Safety of MMR vaccine Mumps virus vaccines (PDF) From the Centers for Disease Control (CDC) Mumps Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP) for the Control and Elimination of Mumps Mumps From the New England Journal of Medicine A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism. Kreesten Meldgaard Madsen, M.D. et al. Volume 347:1477-1482. Nipah Virus From the World Health Organization Nipah Virus Nipah virus fact sheet From the Centers for Disease Control (CDC) Hendra Virus Disease and Nipah Virus Encephalitis Onchocerciasis From the World Health Organization Onchocerciasis fact sheet Onchocerciasis control programs From the Centers for Disease Control Onchocerciasis Filariasis (life cycle, geographic distribution, clinical features, diagnosis) Additional resources OnchoNet The Carter Center River Blindness Program Pertussis From the World Health Organization Pertussis vaccines - WHO position paper From the Centers for Disease Control Pertussis Technical Information on Pertussis Plague The plague is caused by a bacterium known as Yersinia pestis, which primarily infects rodents and their fleas, but which may be transmitted to humans by the bite of rodent fleas, typically when rodents die off. The disease may also be transmitted by inhalation of infected droplets, which may be coughed into the air by a person with plague pneumonia, or by direct exposure to infected blood or tissues. The plague occurs in several forms. Bubonic plague, historically the most common, is characterized by fever, chills, muscle aches, and malaise, associated with the development of an acutely swollen, exquisitely painful lymph node, known as a bubo, near the site of the flea bite. Buboes occur most often in the groin, since fleas usually bite the legs, followed in frequency by the neck and armpit. Septicemic plague is an overwhelming bloodstream infection resulting in fever, obtundation, dangerously low pressure, bleeding abnormalities, and kidney failure. Plague pneumonia results from inhalation of infected droplets or bloodstream spread of the organism to the lungs. Initial symptoms include rapid onset of fever, chills, headache, body aches, weakness, dizziness, and chest discomfort, followed by cough, increasing chest pain, and difficulty breathing. The sputum is often bloody. Severe cases are complicated by respiratory failure, circulatory collapse, and death. Most travelers are at extremely low risk for the plague, even when the disease is known to be present in the animal population. Those who may have contact with rodents or their fleas should bring along a bottle of doxycycline, to be taken prophylactically if exposure occurs. Those less than eight years of age or allergic to doxycycline may take trimethoprim-sulfamethoxazole instead. To minimize risk, travelers should avoid areas containing rodent burrows or nests, never handle sick or dead animals, use appropriate insecticides for any pets, and follow insect protection measures, as described elsewhere. The manufacture of plague vaccine, which was effective against bubonic but not pneumonic plague, was discontinued in 1999. From the World Health Organization (WHO) Plague fact sheet Geographic distribution of the plague (map) Human plague in 1997 (PDF). Weekly Epidemiological Record, Vol. 74, 41, 1999. Human plague in 1998 and 1999(PDF). Weekly Epidemiological Record, Vol. 75, 42, 2000. Plague manual From the Centers for Disease Control (CDC) Plague Plague Home Page Plague General Information Plague Fact Sheet Questions and Answers about Plague Plague: Natural History Plague: Diagnosis Plague Information Prevention of Plague: Recommendations of the Advisory Committee on Immunization Practices (PDF) (comprehensive review; primarily for physicians) From the U.K. Health Protection Agency Plague - general information Interim Guidelines for Action in the Event of a Deliberate Release (PDF) Clinical pictures - plague From the Journal of the American Medical Association Plague as a Biological Weapon From the United States Department of Defense Medical Aspects of Chemical and Biological Warfare (PDF) Severe acute respiratory syndrome (SARS) Severe acute respiratory syndrome (SARS) is a newly recognized illness that appears to be caused by a previously unknown virus belonging to the coronavirus family. The first known outbreak occurred in Guangdong Province in southern China in November 2002, and ultimately led to outbreaks in Hong Kong, Taiwan, Singapore, Viet Nam, and Toronto (Canada). Worldwide, more than 8000 cases and 800 deaths were reported. On July 5, 2003, the World Health Organization announced that the last chain of transmission had been been broken and the outbreak appeared to be over. Four more cases were reported from mainland China in December 2003-January 2004, and an additional eight cases in April 2004. Several other cases have been caused by laboratory exposure to the SARS virus. However, there is no evidence at present that the virus has re-entered the general population. The incubation period for SARS usually ranges from 2-10 days (median 5 days). The first symptom is usually fever, often accompanied by chills, headache, body aches, and malaise. This is typically followed by dry cough and difficulty breathing, at times severe enough to require intubation and mechanical ventilation. The most recent analysis indicates that the overall fatality rate is approximately 15%, ranging from less than 1% in those younger than 25 years old to greater than 50% in those aged 65 years or older. Much is still unknown concerning the mode of transmission. The overwhelming majority of the initial cases occurred in health care workers and in family members or other close contacts of those with the disease. This implied that intimate exposure to secretions from an infected person was necessary to become infected. However, a large number of cases were subsequently reported from a housing estate in Hong Kong, probably caused by contamination of the sewage system by infected fecal material from a man who had SARS and diarrhea. Recent studies have shown that the SARS virus may survive in fecal material for up to four days. Also, the virus may survive for 36 hours on a plastered wall or a formica surface, for 72 hours on a plastic surface or stainless steel, and for 96 hours on a glass slide, raising the possibility that SARS may be acquired from inanimate objects, though this remains unproven. No travel restrictions are recommended at this time. However, since the virus is believed to have originated in civet cats and other wildlife sold for human consumption in open markets, the Centers for Disease Control advises that travelers to Asia should avoid visiting live food markets and having direct contact with civets and other wildlife from these markets. For further information, go to the SARS pages of the World Health Organization, the Centers for Disease Control, and Health Canada. Also see the following: From the New England Journal of Medicine Peiris J. S.M., Yuen K. Y., Osterhaus A. D.M.E., Stöhr K. Current Concepts: The Severe Acute Respiratory Syndrome. N Engl J Med 2003; 349:2431-2441, Dec 18, 2003. Review Article. Olsen S. J., Chang H.-L., Cheung T. Y.-Y., Tang A. F.-Y., Fisk T. L., Ooi S. P.-L., Kuo H.-W., Jiang D. D.-S., Chen K.-T., Lando J., Hsu K.-H., Chen T.-J., Dowell S. F. Transmission of the Severe Acute Respiratory Syndrome on Aircraft. N Engl J Med 2003; 349:2416-2422, Dec 18, 2003. From Emerging Infectious Diseases 2004 SARS Edition Poliomyelitis (polio) Poliomyelitis is a highly contagious infection caused by poliovirus, which is transmitted from person to person through exposure to fecal material or respiratory secretions containing the virus. The incubation period ranges from nine to twelve days. Most poliovirus infections are asymptomatic. Initial symptoms, when they occur, are similar to those of other viral infections and may include fever, headache, muscle aches, malaise, nausea, vomiting, and sore throat. In roughly one in a thousand cases, poliovirus attacks the spinal cord or brainstem, leading to paralysis in various parts of the body, most often the legs. There has been a recent resurgence of polio in west and central Africa, chiefly Nigeria, related in part to a temporary interruption of immunization programs by local authorities in that country. Cases have also been reported from Benin, Botswana, Burkina Faso, Cameroon, Central African Republic, Chad, Ghana, Guinea, Ivory Coast, Mali, Niger, Sudan, and Togo. Poliovirus continues to be transmitted in the Indian subcontinent and in certain countries in the Middle East, particularly Egypt and Afghanistan. All children should receive four doses of inactivated polio vaccine at ages 2 months, 4 months, 6-18 months, and 4-6 years. An accelerated immunization schedule is recommended for children who have not completed their polio immunizations and who may be traveling to places where polio still occurs. Adults who will be traveling to an area where polio is reported and who have never been immunized or whose immunization status is unknown should be given a total of three doses of inactivated polio vaccine separated by at least 4 weeks from each other. Optimally, the third dose should not be given until at least 6 months after the second, but this is generally not feasible. Any adult who completed the full childhood series of polio immunizations but never had a booster as an adult should receive a single dose of polio vaccine before travel to a polio-endemic area. The National Travel Health Network and Centre (U.K.) has recently stated that, if more than 10 years have elapsed since the last dose of polio vaccine, the traveler should be reimmunized. However, the U.S. Centers for Disease Control and Health Canada continue to advise that a single booster during adulthood is sufficient and that there is no evidence that additional doses are necessary. In the United Kingdom, inactivated polio vaccine is available in combination with tetanus and diphtheria vaccine (Revaxis), to facilitate adult reimmunization. Inactivated polio vaccine may cause mild pain or redness at the site of injection. Serious side-effects have never been documented. Since inactivated polio vaccine includes trace amounts of streptomycin, neomycin and polymyxin B, individuals allergic to these antibiotics should not receive the vaccine. Mild illness, including mild diarrhea, is not a contraindication to vaccination. Inactivated polio vaccine has essentially replaced oral polio vaccine in the United States, the United Kingdom, and Canada, because the latter may cause paralytic poliomyelitis, though this is rare. Oral polio vaccine is recommended only for unvaccinated children who will be traveling in less than four weeks to an area where polio is endemic and for mass vaccination campaigns to control polio outbreaks. Polio has been eradicated in the Americas, in Europe, and in the Western Pacific region, which includes large parts of Southeast Asia as well as the Pacific Islands. Travelers to these countries do not require polio boosters. From the World Health Organization (WHO) Poliomyelitis fact sheet Poliomyelitis vaccine Polio vaccines Safety of polio vaccines Global case count Global polio eradication initiative From the Centers for Disease Control (CDC) Poliomyelitis Poliomyelitis Prevention in the United States: Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP) (primarily for physicians) From Health Canada Poliomyelitis Statement on poliomyelitis vaccination for international travellers (PDF) From the National Travel Health Network and Centre (U.K.) Poliomyelitis Poliomyelitis and Changes to Recommendations for Travellers New Polio Vaccine for Travellers Q Fever Q fever, which is caused by a rickettsial organism known as Coxiella burnetii, is primarily a disease of ruminants such as cattle, sheep, and goats, though many other animals may become infected. Humans usually acquire the disease by inhaling dust or aerosols contaminated by body fluids (especially birth products) from infected animals. Most cases occur in those who work directly with animals, such as farmers and slaughterhouse workers. However, since the organism can survive in extreme environmental conditions and only a single organism is necessary for infection, outbreaks may occur after indirect exposure. Less commonly, infection results from ingestion of infected animal products. Q fever is not transmitted from person-to-person, except for rare cases of transmission through breast milk. Symptoms typically include fever, chills, nausea, headache, cough, and body aches. Complications may include pneumonia and hepatitis. Those who have abnormal heart valves may develop endocarditis (heart valve infection), which usually requires surgical replacement of the affected valve. In pregnant women, Q fever may lead to miscarriage. Those who are immuno-compromised due to steroids, cancer, or HIV disease are at greatest risk for complications. Q fever may be treated with doxycycline or tetracycline. Limited data indicate that trimethoprim-sulfamethoxazole and the quinolone antibiotics may also be useful. A vaccine against Q fever is manufactured in Australia (Q-VAX; Commonwealth Serum Laboratories) but may not be available elsewhere. From the Centers for Disease Control (CDC) Q Fever: Information and Guidance for Clinicians Rabies Rabies is a viral infection of the brain and spinal cord that is almost always fatal. The rabies virus is carried in the saliva of infected animals and is typically transmitted through an animal bite, though contamination of any break in the skin with infected saliva may result in rabies. In developing countries, dog bites are responsible for the overwhelming majority of cases. In developed countries, canine rabies is largely controlled through vaccination and most cases are related to wildlife exposure. In the United States, most cases are attributable to raccoons, skunks, and bats. The incubation period usually ranges from 20 to 90 days, but may be substantially longer. Initial symptoms may include numbness, tingling, and itching at the site of the healed bite wound, as well as fever, headache, malaise, mood swings, and personality changes. This is followed several days later by hydrophobia (the classic rabies symptom), producing uncontrollable spasms at even the sight of water, as well as aerophobia (fear of air), hallucinations, agitation, and increasing lethargy, progressing inexorably to coma. A smaller number of rabies patients develop paralysis as their main symptom, followed by mental deterioration and coma. Between 1980 and 1992, ten American travelers died from rabies contracted while abroad, indicating a low but measurable risk. Administration of rabies immune globulin and rabies vaccine after an animal bite or scratch, as described below, is highly effective in preventing rabies. Rabies vaccine before travel is therefore reserved for those at high risk for rabies exposure, such as animal handlers and spelunkers (cave explorers), and for those who may be at risk for animal bites and may not have access to postexposure treatment if necessary, either because they will be visiting remote, inaccessible areas or because supplies of the appropriate biologicals may not be available. Some poorer countries may not have rabies immune globulin or may offer only one of the older, brain-tissue-derived rabies vaccines, which are much less effective than tissue- and avian-culture vaccines, are painful, and sometimes cause neuroparalytic reactions, including meningoencephalitis, mononeuritis multiplex, tranverse myelitis, and ascending paralysis of the Landry type. Travelers who require rabies vaccine before departure should receive a total of three 1.0-ml doses, injected into the deltoid muscle, on days 0, 7, and 21 or 28. Three types of vaccine are currently licensed in the United States: human diploid cell vaccine (HDCV), rabies vaccine adsorbed (RVA), and purified chick embryo cell vaccine (PCEC). All appear to be safe and effective. The most frequent reaction is pain, swelling, redness, or itching at the injection site. Other side-effects may include headache, nausea, abdominal pain, muscle aches, or dizziness. Allergic reactions are occasionally reported after booster doses of HDCV. The three-dose series appears to be effective for at least two years. Those who remain at risk for rabies two years after immunization should either be tested for rabies antibodies or given a single booster dose of vaccine. Immunosuppressed individuals who receive rabies vaccine should be tested for rabies antibodies before departure. All animal bites and scratches must be promptly and thoroughly cleaned with large amounts of soap and water, whether or not the person has received rabies vaccine, and the local health authorities should be contacted. If there is a risk for rabies and the victim has not been vaccinated, he or she should immediately receive rabies immune globulin (infiltrating as much as possible into the bite site and giving the remainder intramuscularly) and should immediately start a four dose series of rabies vaccine, to be given on days 0, 3, 7, and 14. (It was previously advised that a fifth dose should be given on day 28, but the U.S. Advisory Committee on Immunization Practices voted in June 2009 to change the recommendation.) Those who have been previously vaccinated should be given a dose of rabies vaccine on days 0 and 3 and no immune globulin. In a country where rabies is endemic, postexposure treatment should be given whether or not the attack was "provoked". Pregnancy is not a contraindication to postexposure treatment. The only rabies immune globulin available in the United States and Canada is human rabies immune globulin. The recommended dosage after rabies exposure is 20 IU/kg. Two other types of rabies immune globulin, non-pepsin-digested (non-purified) equine rabies immune globulin (ERIG) and ammonium-sulfate-precipitated (purified) ERIG, may be given in other countries. Purified ERIG appears to be considerably safer: only 0.0025% of those receiving it develop anaphylactic (severe allergic) reactions, compared to 3.8% of those receiving the non-purified preparation. The recommended dosage of ERIG is 40 IU/kg. Antimalarial drugs may interfere with the immune response to rabies vaccine when it is given in a dosage of 0.1 ml by the intradermal route, which is sometimes done to reduce costs. Rabies vaccine should not be given by the intradermal route if there isn't time to complete immunization before starting malaria prophylaxis. Any traveler who receives treatment for rabies exposure while abroad should be reassessed after returning home. NOTICE: On April 2, 2004, the manufacturer of IMOVAX Rabies Vaccine (Aventis Pasteur) announced that several lots of vaccine had been found to contain live rabies virus that had not been fully inactivated. In the United States, lot numbers X0667-2, X0667-3, W1419-2, and W1419-3, which were distributed from September 23, 2003 through April 2, 2004, have been recalled. For a list of the lots recalled in other countries, go to the Centers for Disease Controlwebsite. No unusual adverse events associated with the recalled vaccine have been reported to date. Health care providers should contact persons who received recalled vaccine and follow the recommendations outlined by the Centers for Disease Control. Any persons who received rabies vaccine between September 23, 2003, and April 2, 2004, should contact their physician to determine if they received vaccine from one of the recalled lots and, if so, whether they need further evaluation. For additional information, contact the Aventis Pasteur Medical Information Services Department, telephone 800-835-3587, or go to their website at http://www.vaccineshoppe.com . From the World Health Organization (WHO) Rabies fact sheet Rabies vaccine Safety of rabies vaccine WHO Recommendations on Rabies Post-Exposure Treatment Rabies vaccines (PDF) RABNET (WHO data bank which offers online access to information on rabies prevalence, diagnosis, surveillance, and control in humans and animals from almost all countries in the world) WHO World Survey of Rabies: 1997; 1996; 1995; 1994; 1993 From the Centers for Disease Control Use of a Reduced (4-Dose) Vaccine Schedule for Postexposure Prophylaxis to Prevent Human Rabies Human Rabies Prevention - United States, 2008 Recommendations of the Advisory Committee on Immunization Practices (ACIP) Rabies Common Questions and Answers about Rabies CDC Rabies Homepage From Health Canada Rabies Statement on travellers and rabies vaccine From the National Travel Health Network and Centre (U.K.) Rabies From the U.K. Health Protection Agency Rabies: general information (PDF) Rabies: frequently asked questions (PDF) Memorandum on rabies: prevention and control (PDF) Rabies and travel (CDR Weekly) Relapsing Fever Relapsing fever is caused by bacteria known as spirochetes, closely related to the organisms that cause Lyme disease. The bacteria may be transmitted to humans by either ticks or lice. The illness is characterized by periods of fever, chills, headaches, body aches, muscle aches, and cough, alternating with periods when the fever subsides and the person feels relatively well. Complications may include bleeding abnormalities, pneumonia, meningitis, cranial nerve palsies, hemiplegia, and coma. Tetracycline, erythromycin, and penicillin have all been used to treat relapsing fever. The first dose of antibiotic is often followed by a severe reaction (Jarisch-Herxheimer reaction) marked by fever, shaking chills, and a fall in blood pressure. There is no vaccine for relapsing fever. However, a recent study in Israel showed that tick-borne relapsing fever could be prevented by giving doxycycline (200 mg the first day, then 100 mg/day for four days) to those with suspected tick bites (see T. Hasin MD et al, New England Journal of Medicine 2006; 355:148-55). Travelers to areas where relapsing fever occurs should be sure to follow tick precautions, as outlined elsewhere, and exercise good personal hygiene at all times. Rift Valley Fever Rift Valley fever is a viral infection that primarily affects domesticated animals, chiefly sheep, cattle, goats, and camels, but may involve humans as well. Historically, the disease has been limited to Africa, but a major outbreak was recently reported from Saudia Arabia and Yemen, demonstrating the potential of Rift Valley fever to spread to other regions. The disease is usually transmitted by mosquitoes, but may also be acquired by direct exposure to infected animals or their tissues. Aerosol transmission has been documented. Most cases occur in people who work with livestock. Outbreaks typically occur at times of heavy rainfall, when mosquitoes proliferate. The incubation period ranges from two to six days. Initial symptoms may include fever, chills, muscle aches, backache, headache, nausea, vomiting, and light sensitivity. Most people recover uneventfully in four to seven days, but the course may be complicated by loss of vision (retinitis), liver inflammation (hepatitis), kidney failure, excessive bleeding (hemorrhage), inflammation of the brain (encephalitis), or death. Experimental evidence suggests an antiviral drug called ribavirin may be effective, but this has not yet been tested in humans. No vaccine is currently available. The best means of prevention is to follow insect protection measures and to wear gloves and protective garments when handling animal tissues or caring for infected patients. Strict barrier and respiratory precautions are essential when patients with suspected Rift Valley fever are admitted to the hospital. From the World Health Organization (WHO) Rift Valley Fever Fact Sheet From the Centers for Disease Control (CDC) Viral Hemorrhagic Fevers Fact Sheet on Rift Valley Fever Rift Valley Fever Fact Sheet Rift Valley Fever Distribution Maps Rubella From the World Health Organization (WHO) Rubella vaccine Safety of MMR vaccine From the Centers for Disease Control (CDC) Rubella Rubella Notice to Readers: Revised ACIP Recommendation for Avoiding Pregnancy After Receiving a Rubella-Containing Vaccine From the New England Journal of Medicine A Population-Based Study of Measles, Mumps, and Rubella Vaccination and Autism. Kreesten Meldgaard Madsen, M.D. et al. Volume 347:1477-1482. Schistosomiasis Schistosomiasis is a parasitic infection acquired by swimming, wading, bathing, or washing in fresh water that contains snails and that has been contaminated by feces or urine carrying parasite eggs from infected persons. Once in the water, the eggs hatch, releasing an immature form of the parasite that infects snails. The parasite undergoes further development in the snail, emerging in a stage that has the capacity to penetrate intact human skin. Once inside its human host, the parasite matures into an adult worm and lays eggs, which may migrate to bladder (urinary schistosomiasis) or to the intestines or liver (intestinal or hepatic schistosomiasis), depending upon the species. Early symptoms may include fever, loss of appetite, weight loss, abdominal pain, weakness, headaches, joint and muscle pains, diarrhea, nausea, and cough, but most infections are asymptomatic at first. Long-term complications may include kidney failure (urinary schistosomiasis) or malabsorption, enlargement of the liver and spleen, engorgement of the esophageal blood vessels, and accumulation of fluid in the abdominal cavity (intestinal or hepatic schistosomiasis). Occasionally, eggs may be deposited in the brain or spinal cord, leading to seizures or paralysis. The drug of choice for most forms of schistosomiasis is praziquantel. There is no vaccine at present. Travelers to Africa, especially those who swim, wade, or raft in fresh water, are at greatest risk for schistosomiasis. A recent study from Europe found that most infections were imported from Mali, Senegal, Ghana, Democratic Republic of the Congo, and Uganda. Those traveling for missionary or volunteer work or as expatriates are at highest risk. The disease is occasionally reported after travel to Asia or South America. The key to prevention is avoiding bodies of fresh water, such as lakes, ponds, streams, and rivers, in places where schistosomiasis might occur. Salt water and chlorinated pools are thought to carry no risk of schistosomiasis. Water for bathing or showering should be heated to 150 degrees F for at least 5 minutes or held in a storage tank for at least 3 days. Toweling oneself dry after unavoidable or accidental exposure to contaminated water may reduce the likelihood of schistosomiasis, but does not reliably prevent the disease and is no substitute for the precautions above. Chlorinated swimming pools are considered safe. From the World Health Organization Schistosomiasis fact sheet Global schistosomiasis atlas From the Centers for Disease Control Schistosomiasis Fact Sheet on Schistosomiasis Schistosomiasis (life cycle, geographic distribution, clinical features, diagnosis, treatment) From Eurosurveillance Imported schistosomiasis in Europe: preliminary data for 2007 from TropNetEurop From the U.K. Health Protection Agency Schistosomiasis in travellers From the American Journal of Tropical Medicine and Hygiene DJ Nicolls et al. Characteristics of Schistosomiasis in Travelers Reported to the GeoSentinel Surveillance Network 1997–2008 From TDR Schistosomiasis Schistosomiasis disease information Additional resources Schistosomiasis control initiative Smallpox The last case of smallpox in the United States occurred in 1949. In 1972, routine immunization with smallpox vaccine was discontinued in the United States. In 1978, the last case in the world occurred in Somalia. Two years later, the World Health Organization declared that smallpox had been eradicated. Only two laboratories, one in the United States and one in Russia, still have stocks of smallpox virus, which have been maintained for research purposes. There have been reports that the Russians manufactured large quantities of virus for possible wartime use. The question is whether or not some of the Russian supplies might have fallen into other hands, though there is no evidence at present that this happened. Because of recent concern that smallpox may recur, though there have been no cases for more than 20 years, the illness should be reviewed. The incubation period for smallpox ranges from 7-to-17 days (usually 12-to-14 days), which is relatively long for a viral illness. Initial symptoms consist of high fevers, malaise, headache, and backache, followed by the appearance of small raised red spots (maculopapular rash) that begin inside the mouth and on the face and forearms, then spread sequentially to the legs and trunk. The skin lesions evolve into small blisters, then pustules. Scabs develop, which eventually separate, leaving pitted scars. In its early stages, the rash may resemble that of chickenpox, with two key differences. (1) In smallpox, the lesions are densest on the face and outermost extremities, whereas in varicella, the greatest number of lesions are on the trunk. (2) In smallpox, all lesions are at the same stage of development, whereas in varicella, the lesions are at different stages of evolution, i.e. some may be blisters while others are scabbing. A small percentage of patients develop flat-type smallpox, characterized by large, flat lesions with a soft, velvety texture, or hemorrhagic smallpox, characterized by severe toxicity, diffuse ecchymoses (bleeding into the skin), and high mortality. Partially immune individuals (including those who were vaccinated many years ago) may develop a milder illness with an abbreviated course. Complications include arthritis, osteomyelitis, keratitis, encephalitis, and pulmonary edema. Skin lesions should be cultured to confirm the diagnosis. Specimens must be referred to a specialized high-containment laboratory. Once the presence of smallpox is established, additional cases do not require laboratory confirmation. Smallpox patients must be confined to negative pressure isolation rooms. Visitors and staff must wear gowns, gloves, and masks at all times. In a large outbreak, patients who are less ill should be cared for at home. Patients do not become infectious until the rash appears and remain infectious until all scabs separate. Those who have been exposed to smallpox but are asymptomatic do not need to be quarantined, but must be closely observed for 17 days after their last exposure to the disease. If they become febrile during this time, they must be immediately quarantined, preferably at home, until the fever has resolved and it is certain that they do not have smallpox. The ability to identify and quarantine potential smallpox cases before they become infectious is of great assistance in controlling an outbreak. There is no known treatment for smallpox. Historically, overall mortality was 30% in unvaccinated patients. However, there has never been a smallpox outbreak in a country with modern hospital and ICU facilities. Given the substantial advances in supportive care, outcomes would probably be considerably better if an outbreak were to occur today in an industrialized country. However, mortality would be high in a developing nation. Smallpox vaccine consists of live vaccinia virus, an organism that is closely related to the virus which causes smallpox, but which typically causes only a mild, localized skin infection when injected into humans. Rare complications of smallpox vaccine include progressive or generalized vaccinia infection, postvaccinial encephalitis, and eczema vaccinatum, characterized by vaccinial infection of current or previous eczematous skin lesions. The duration of protection from smallpox vaccine is thought to be about ten years, so it is presumed that those who were vaccinated before the 1970's are no longer immune. The Centers for Disease Control has stockpiled approximately 12-15 million doses of smallpox vaccine, which were produced in the 1970's and may have lost their potency. Current supplies are being reserved for use in a possible outbreak situation. Current supplies are being reserved for use in a possible outbreak situation. Studies are in progress to determine if the vaccine will retain its effectiveness when diluted, to produce more doses if needed. New vaccines are under development, but will not be available for the foreseeable future. From the World Health Organization (WHO) Smallpox fact sheet Frequently asked questions and answers on smallpox Smallpox and its eradication. F. Fenner, D.A. Henderson, I. Arita, Z. Jezek, I.D. Ladnyi (1500-page book published in 1988) Smallpox (Weekly Epidemiological Record) From the Public Health Laboratory Service (U.K.) Smallpox - general information Smallpox pictures (PDF) Interim Guidelines for Action in the Event of a Deliberate Release (PDF) From the Centers for Disease Control (CDC) Smallpox From Health Canada Statement on Smallpox Vaccination From the Journal of the American Medical Association (JAMA) Smallpox as a Biological Weapon From Emerging Infectious Diseases Developing New Smallpox Vaccines, S.R. Rosenthal et al. From the United States Department of Defense Medical Aspects of Chemical and Biological Warfare (PDF) Swine flu An outbreak caused by a novel strain of H1N1 influenza, commonly called "swine flu", began in Mexico in March 2009 and spread rapidly to many other countries. The virus contains a unique combination of swine, avian, and human influenza gene segments that had not been previously observed. Initial reports from Mexico indicated a high fatality rate in previously healthy young adults and older children, raising concerns that a worldwide pandemic might occur, similar to 1918. However, subsequent data from Mexico, as well as experience from other countries, indicated the H1N1 strain from 2009 is not nearly as lethal as some people initially feared. Preliminary data indicate that up to one-third of those greater than 60 years of age have antibodies against the novel H1N1 virus, whereas protective antibodies are found much less frequently in children and younger adults (see MMWR). This is consistent with the clinical experience so far, which indicates that the most severe cases are occurring in those younger than age 60. The World Health Organization does not recommend any travel restrictions at this time. To protect yourself from H1N1 influenza, wash your hands regularly and avoid close contact with anyone who is coughing or sneezing. Routine use of face masks is not recommended. The symptoms of H1N1 influenza include fever, cough, sore throat, body aches, headache, chills and fatigue, similar to seasonal influenza. Any traveler who develops flu-like symptoms after travel to a country which has reported H1N1 influenza should immediately seek medical attention. Empiric treatment with oseltamivir (Tamiflu) and zanamivir (Relenza) should be considered for suspected cases, though a small number of Tamiflu-resistant isolates have been described. The virus is resistant to amantadine and rimantadine. Vaccination against novel H1N1 influenza is recommended for everyone, except those allergic to the vaccine or one of its components. For further information on novel H1N1 influenza (swine flu), go to the World Health Organization and the Centers for Disease Control. The following is the latest update from the World Health Organization: As of 12 July, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18337deaths. WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and Member States and through monitoring of multiple sources of information. Situation update: Worldwide, overall pandemic influenza activity remains low. The most active areas of pandemic influenza virus transmission currently are in parts of South Asia, West Africa, and Central America. In the temperate zone of the southern hemisphere, pandemic and seasonal influenza activity has remained low during the first half of the southern hemisphere winter, except in South Africa, where increased detections of primarily seasonal influenza viruses (type B and H3N2) were reported during late June and early July 2010. Seasonal influenza H3N2 viruses continue to circulate at varying levels across parts of the Americas, Africa, and Southeast Asia. Increased seasonal influenza activity continues to be observed in several countries of Central America. To date, most countries of the temperate zone of the southern hemisphere, with the exception of South Africa, have reported low overall levels of respiratory disease activity and low to sporadic levels of pandemic and seasonal influenza virus circulation during the first half of the southern hemisphere winter season. Pandemic influenza viruses have been detected only sporadically or at low levels in most of these countries. As reported last week, South Africa began observing a sharp increase in the proportion of sentinel respiratory samples testing positive for influenza virus (primarily seasonal influenza B and H3N2) during late June 2010, reaching a peak of ~50% detection rate during the first week of July 2010, and falling to ~40% during the second week of July 2010. In Chile (as of late June 2010) and Argentina (as of early July 2010), the most recent available data show that influenza activity remains sporadic in Argentina and low in Chile (~5% respiratory samples tested positive for influenza, 84% of which were pandemic virus with small numbers of seasonal influenza H3N2 and type B detected as well). In both Chile and Argentina, RSV has been the predominant circulating respiratory virus since mid-April 2010. In Australia, as of the last week of June 2010, overall rates of ILI remained low and below levels observed during the same period in past three winter seasons. Although a small cluster of pandemic influenza cases, including a few hospitalized cases, were recently detected in the Northern Territory of Australia, pandemic and seasonal influenza virus detections remain otherwise sporadic, albeit slightly increased during late June and early July 2010. Similarly, in New Zealand, rates of ILI have remained low and below the seasonal baseline, with only sporadic detections of pandemic and seasonal H3N2 viruses through the first week of July 2010. In both Australia and New Zealand, current levels of ILI are similar to those observed during the same period in 2008, when the influenza season was noted to have arrived and peaked late in winter. In Asia, overall pandemic influenza activity remains low to sporadic, except in parts of southern and western India, Malaysia, and Singapore. As reported last week, in India, transmission of pandemic influenza virus remains active but stable in the southern state of Kerala. The extent of illness in the community is currently being assessed and monitored by the Government of India. Similar numbers of new cases, including small numbers of fatal cases, have been reported on a weekly basis since transmission first increased during mid-June 2010. Recent, small increases in pandemic influenza virus circulation have also been observed since mid-June 2010 in other southern and western states of India, particularly in the western state of Maharashtra. In Singapore, levels of ARI increased during the first two weeks of July 2010; however, the intensity of pandemic influenza virus transmission has declined during June and July 2010 after peaking in May 2010. The proportion of patients with ILI testing positive for pandemic influenza virus in Singapore remained stable (14-16%) during first two weeks of July 2010. In addition, substantial co-circulation of seasonal influenza H3N2 viruses (with pandemic H1N1 virus) was detected in Singapore throughout May and June 2010. In Malaysia, numbers of new cases of pandemic influenza continued to decline; overall pandemic influenza activity fell substantially in June and early July 2010 after peaking during mid-April to mid-May 2010. Low levels of seasonal influenza type B viruses (and to much lesser extent pandemic influenza virus) continue to circulate across northern and southern China as levels of ILI remain stable and near seasonal levels seen in the same period in recent years. Low levels of pandemic and seasonal influenza (H3N2 and type B) viruses also continued to circulate in Hong Kong SAR (China), Chinese Taipei, and parts of Thailand. In the tropical regions of the Americas, overall pandemic and seasonal influenza activity remained low, except in parts of Central and South America, where there has been recent active co-circulation of pandemic and seasonal influenza H3N2 viruses. The majority of recent active transmission of pandemic influenza virus has been reported in Colombia, Costa Rica, and to a lesser extent in Cuba. In Colombia, although low level circulation of pandemic influenza viruses has persisted throughout the first half 2010, a second period of active transmission began in mid-May 2010, peaked in June 2010, has now largely subsided during the second of week of July 2010. Similarly, in Costa Rica, low level circulation of pandemic virus has persisted throughout 2010, however, there has been a recent resurgence in active transmission (though less intense than the initial 2009 wave) of pandemic influenza virus during June 2010. As reported previously, in Panama, a sharp increase in the circulation influenza A viruses (particularly H3N2, but also small numbers of pandemic H1N1) was reported over the month of June 2010; a high intensity of respiratory diseases and a moderate impact on healthcare services continued to be reported during the second week of July 2010. In Nicaragua, recent active transmission of seasonal influenza H3N2 viruses, which began during late May 2010 and peaked during mid June 2010, appears to have largely subsided during recent weeks. Many countries in the region continue to report ongoing co-circulation of other respiratory viruses, most notably RSV. In sub-Saharan Africa, the current situation is largely unchanged since the last update. Pandemic and seasonal influenza activity continues to be observed in several countries. Ghana, in West Africa, continued to have a sustained resurgence in circulation of pandemic influenza virus during June 2010, more than several months after the first period of pandemic activity peaked (early April 2010). Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, particularly in Cameroon, where an increase in influenza type B virus circulation was observed during June 2010. Small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern and southern Africa; the most recent detections have been reported in Kenya and South Africa. Overall, in the temperate regions of the northern hemisphere (North America and Europe), pandemic and seasonal influenza viruses have been detected only sporadically or at very low levels during the past month. Tetanus Tetanus is a disease, commonly known as "lockjaw," caused by a bacterium called Clostridium tetani. The incubation period usually ranges from 3 days to 3 weeks. Tetanus occurs when the spores of Clostridium tetani are introduced into a cut or wound. The organisms germinate, then release a toxin that causes severe, painful muscle spasms, first in the jaw, then in the neck, chest, back, arms, and legs. Uninhibited muscle spasms may lead to fractures, swallowing difficulties, aspiration, or asphyxia. Cardiac arrhythmias may occur, as well as wide swings in temperature and blood pressure. Tetanus antitoxin must be promptly administered, in conjunction with an antibiotic, usually metronidazole. Aggressive supportive measures, including mechanical ventilation, play an essential role. Even when medical care is optimal, the death rate ranges from 10-20%. The elderly are at highest risk for tetanus, because many have never been fully immunized. Tetanus vaccine consists of tetanus toxin that has been inactivated by formaldehyde and adsorbed onto aluminum salts to increase its effectiveness. The vaccine is routinely given, in combination with diphtheria and pertussis vaccines, to all children at ages 2 months, 4 months, 6 months, 15-18 months, and 4-6 years, followed by tetanus-diphtheria vaccine every 10 years thereafter. All adults who completed the recommended childhood immunizations but have not received tetanus-diphtheria vaccine within the past 10 years should be given a booster. Unvaccinated persons more than seven years of age should receive three doses of adult tetanus-diphtheria vaccine. The first two doses should be separated by 4-8 weeks, and the third dose should be given 6-12 months after the second. An accelerated immunization schedule is recommended for partially immunized children who will be traveling to developing countries. Reactions to tetanus-diphtheria vaccine may include fever or discomfort and swelling at the injection site. Severe allergic reactions, which occur rarely, are a contraindication to further doses of the vaccine. All cuts or wounds should be promptly and thoroughly cleansed. From the World Health Organization Tetanus vaccine Tetanus toxoid vaccine From the Centers for Disease Control (CDC) Tetanus Tetanus (lockjaw) Tick-Borne Encephalitis Tick-borne encephalitis is a viral infection of the central nervous system transmitted by tick bites, usually after travel to rural or forested areas. The disease may also be acquired by ingesting unpasteurized dairy products. Two subtypes have been identified, sometimes known as Russian spring/summer encephalitis and Central European encephalitis, but there is little difference between them. The disease is reported from Scandinavia, Western Europe, Central Europe, the former Soviet Union, and East Asia. The peak incidence is from April through August. The incubation period is usually from one to two weeks, but may vary. The disease typically begins as a flu-like illness, including fever, headache, and vomiting, followed by the development of neurologic symptoms, including neck stiffness, dizziness, tremors, drowsiness, delirium, and coma. Neurologic damage may be permanent, causing chronic headaches, difficulty concentrating, muscle weakness or loss of balance. A small percentage of cases are fatal. The disease is rarely severe in children less than four years old. Three vaccines have been developed for tick-borne encephalitis. The first, called FSME Immun (Baxter AG), consists of inactivated, purified whole virus. The vaccine is manufactured in Austria and approved for use in a number of European countries, but is not available in the United States. In Canada, the vaccine can be obtained through the Emergency Drug Release Program at (613) 941-2108 or at the Bureau of Biologics at (613) 941-2114. A full series consists of three doses over a one-year period (at times 0, 1, and 12 months), so complete immunization is not practical for most travelers. Because a previous version of this vaccine caused high fevers in infants and young children (probably due to the absence of albumin, which has been included in the current product), FSME Immun is recommended only for those over 16 years old. Serious reactions have not been documented in older children and adults. The vaccine has been suspected of causing an exacerbation of autoimmune diseases, but a cause-and-effect relationship has not been confirmed. Another vaccine is Encepur (Chiron Behring), which is manufactured in Germany and available in several European countries, but not North America. Like FSME Immun, the usual schedule consists of three doses over a one-year period. However, limited data indicate that an accelerated schedule, consisting of two doses separated by one week, may confer immunity in most people. A third dose should be given three-to-four weeks later, followed by a fourth dose in one year's time. A third vaccine for tick-borne encephalitis, called Encevir, is produced in Russia. The vaccine was temporarily withdrawn in May 2010 after a number of people receiving the vaccine experienced side-effects. There are no proven treatments for tick-borne encephalitis. Gamma globulin is sometimes used, but the effectiveness is unproven and there is evidence that it might actually lead to a more severe infection. Tick precautions, as described elsewhere, are strongly advised for travel to rural or forested areas, especially in the spring or summer, in countries where tick-borne encephalitis is known to occur. From the World Health Organization Tick-borne encephalitis: disease burden and vaccines Safety of Tick Borne Encephalitis Vaccine From Health Canada Statement on tick-borne encephalitis European Tick Borne Encephalitis From the Centers for Disease Control (CDC) Tick-Borne Encephalitis Tick-Borne Encephalitis From Eurosurveillance A survey on cases of tick-borne encephalitis in European countries The changing incidence of tickborne encephalitis in Europe From the International Scientific Working Group on TBE Home page Map of endemic areas Number of reported cases of TBE from various European countries and Russia From the National Travel Health Network and Centre (U.K.) Tick-borne encephalitis Travelers' Diarrhea Travelers' diarrhea is the most common travel-related infection. It may be caused by many different organisms, including bacteria such as E. coli, Salmonella, Shigella, Campylobacter, Aeromonas, Plesiomonas, and vibrios; parasites such as Giardia, Entamoeba histolytica, Cryptosporidium, and Cyclospora; and viruses. In addition to diarrhea, symptoms may include nausea, vomiting, abdominal pain, fever, sweats, chills, headache, and malaise. The chief complication is dehydration, which may become severe, especially in warmer climes. The best means of prevention is to avoid any questionable foods or beverages. Do not drink tap water unless it has been boiled, filtered, or chemically disinfected. Do not drink unbottled beverages or drinks with ice. Do not eat fruits or vegetables unless they have been peeled or cooked. Avoid cooked foods that are no longer piping hot. Cooked foods that have been left at room temperature are particularly hazardous. Avoid unpasteurized milk and any products that might have been made from unpasteurized milk, such as ice cream. Avoid food and beverages obtained from street vendors. Do not eat raw or undercooked meat or fish, including ceviche. Some types of fish may contain poisonous biotoxins even when cooked. Barracuda in particular should never be eaten. Other fish that may contain toxins include red snapper, grouper, amberjack, sea bass, and a large number of tropical reef fish. Although antibiotics may be taken prophylactically to prevent travelers' diarrhea (i.e. taken on a daily basis before symptoms have a chance to occur), this isn't generally recommended because starting antibiotics after diarrhea begins works well and because increased antibiotic use might lead to a greater incidence of side-effects and the selection of resistant organisms. Prophylactic antibiotics might be appropriate for situations in which diarrhea might prove unusually troublesome (i.e. business trip, diplomatic mission, athletic event) or for travelers who are immunocompromised or who have a history of intestinal disorders, such as those with inflammatory bowel disease. Appropriate regimens include ciprofloxacin (Cipro)(PDF) or levofloxacin (Levaquin)(PDF) 500 mg once daily or (less effectively) trimethoprim-sulfamethoxazole (Bactrim; Septra) one double-strength tablet daily. Bismuth subsalicylate (Pepto-Bismol) (two tablets or two ounces four times daily) will reduce the likelihood of travelers' diarrhea, but few take this because it is inconvenient. Side-effects may include black tongue, black stools, nausea, constipation, and ringing in the ears (tinnitus). Bismuth subsalicylate should not be taken by those with aspirin allergy, kidney disease, or gout, and should not be taken for more than three weeks. Quinolone antibiotics may bind to metallic cations such as bismuth; they should not be taken concurrently. The standard recommendation is for travelers at risk to bring along an antibiotic and an antidiarrheal drug to be started promptly if significant diarrhea occurs, defined as three or more loose stools in an 8-hour period or five or more loose stools in a 24-hour period, especially if associated with nausea, vomiting, cramps, fever or blood in the stool. A quinolone antibiotic is usually prescribed: either ciprofloxacin (Cipro)(PDF) 500 mg twice daily or levofloxacin (Levaquin)(PDF) 500 mg once daily for a total of three days. Quinolones should not be given to children, pregnant women, or anyone with a history of quinolone allergy. Alternative regimens include a three day course of rifaximin (Xifaxan) 200 mg three times daily or azithromycin (Zithromax) 500 mg once daily. Rifaximin should not be used by those with fever or bloody stools and is not approved for pregnant women or those under age 12. Azithromycin should be avoided in those allergic to erythromycin or related antibiotics. For children, the dosage of azithromycin is 10 mg/kg on day 1, up to 500 mg, and 5 mg/kg on days 2 and 3, up to 250 mg. Another option is trimethoprim/sulfamethoxazole (Bactrim), which is used less often today because of increasing bacterial resistance but may be appropriate for children or those unable to tolerate other antibiotics. The dosage is one double-strenth tablet twice daily for adults and 5 mg/kg trimethoprim/25 mg/kg sulfa twice daily for children. Trimethoprim-sulfamethoxazole should not be given to pregnant women or those with a history of sulfa allergy. An antidiarrheal drug such as loperamide (Imodium) or diphenoxylate (Lomotil) should be taken as needed to slow the frequency of stools, but not enough to stop the bowel movements completely. Diphenoxylate (Lomotil) and loperamide (Imodium) should not be given to children under age two. Most cases of travelers' diarrhea are mild and do not require either antibiotics or antidiarrheal drugs. Adequate fluid intake is essential. Oral rehydration solutions, which are rich in salt and sugar, are widely available and highly effective. If fluids that do not contain salt are used, plain salted foods, such as crackers, are recommended. Dairy products should be avoided until diarrhea has subsided, as these are often difficult to digest while the intestine is inflamed. If diarrhea is severe or bloody, or if fever occurs with shaking chills, or if abdominal pain becomes marked or if diarrhea persists for more than 72 hours, medical attention should be obtained, if possible. From the World Health Organization (WHO) Enterohaemorrhagic Escherichia coli (EHEC) Guide on Safe Food for Travelers From the Centers for Disease Control (CDC) Travelers' Diarrhea (Yellow Book) Travelers' Diarrhea: frequently asked questions Safe Food and Water Treatment of Water to Make it Safe for Drinking Escherichia coli O157:H7 Salmonellosis Shigellosis From Health Canada Statement On Persistent Diarrhea In The Returned Traveller Gastrointestinal Illness while Travelling Statement on Travelers' Diarrhea Diarrhea Associated with Travel to the Tropics From "Health Information for Overseas Travel" (U.K.) Prevention of travellers' diarrhoea and other food and water-borne diseases From Emerging Infectious Diseases S. Altekruse et al., Emerging Foodborne Diseases Other sites Giardia Club Tuberculosis From the World Health Organization (WHO) Tuberculosis From the Centers for Disease Control Tuberculosis Division of Tuberculosis Elimination From Health Canada The Risk and Prevention of Tuberculosis in Travellers Tuberculosis Screening and the International Traveller Tularemia From the Centers for Disease Control (CDC) Tularemia Typhoid Fever Typhoid fever is caused by ingestion of food or water contaminated by a species of Salmonella known as Salmonella typhi. The organism may persist in the stool after signs of illness have resolved and may be passed to others if personal hygiene is poor, especially if the individual is involved in preparing food. The incubation period usually ranges from one to two weeks, but may be as long as two months. Fever occurs in virtually all cases. Other symptoms may include headache, malaise, muscle aches, dizziness, loss of appetite, nausea, and abdominal pain. Either diarrhea or constipation may occur. Possible complications include intestinal perforation, intestinal bleeding, confusion, delirium, or rarely coma. Because reports of resistance to older antibiotics are becoming more frequent, typhoid fever is usually treated with one of the quinolone antibiotics, such as ciprofloxacin or levofloxacin, generally by mouth. An alternative drug is ceftriaxone, which must be given by injecton. Typhoid vaccine is generally given in an oral form (Vivotif Berna) consisting of four capsules taken on alternate days until completed. The capsules should be kept refrigerated and taken with cool liquid. Protection is achieved seven days after the last dose. Side-effects are uncommon and may include abdominal discomfort, nausea, and rash or hives. Oral typhoid vaccine should not be taken with antibiotics, because they may interfere with its effectiveness. If all four doses are not taken, the entire series must be restarted to achieve protection. The alternative is an injectable polysaccharide vaccine (Typhim Vi; Aventis Pasteur Inc.) (PDF) given as a single 0.5 cc intramuscular injection. Immunity is conferred seven days after vaccination. Adverse reactions, which are uncommon, may include discomfort at the injection site, fever and headache. In February 2005, the manufacturer announced a temporary shortage of the injectable vaccine, which it attributed to increased demand and which it expected to last until early April 2005. The oral vaccine is approved for travelers at least six years old, whereas the injectable vaccine is approved for those aged two or above. A liquid formulation of the oral vaccine has been shown to be effective in children as young as two years old, but has not yet been approved in the United States. The efficacy of both vaccines appears comparable, generally 50-70% in different studies. Boosters are recommended after five years for the oral vaccine and two years for the polysaccharide vaccine. The safety of typhoid vaccine during pregnancy is unknown. If typhoid immunization is necessary during pregnancy, the injectable polysaccharide vaccine (Typhim Vi) is probably preferable, because it does not contain live bacteria. Oral typhoid vaccine is safe in HIV-infected individuals as long as their CD4 lymphocyte counts remain above 200. Breastfeeding is probably protective against typhoid fever in infants. Because the efficacy of typhoid vaccine is limited and because many other infections can be acquired from contaminated food and beverages, immunization against typhoid does not in any way diminish the importance of following food and water precautions. From the World Health Organization (WHO) Typhoid fever Typhoid fever fact sheet Typhoid and paratyphoid enteric fevers Typhoid vaccine Safety of typhoid vaccines Typhoid vaccines (PDF) (WHO position paper) From the Centers for Disease Control (CDC) Typhoid Fever (Yellow Book) Typhoid Fever: Frequently Asked Questions Technical Information on Typhoid Fever Typhoid Immunization: Recommendations of the Advisory Committee on Immunization Practices (PDF) (comprehensive discussion; chiefly for physicians) From Health Canada Typhoid fever Statement on overseas travelers and typhoid fever Louse-Borne Typhus Louse-borne typhus is a rickettsial infection transmitted by the human body louse. (Head lice and pubic lice do not transmit the disease.) Infection occurs when a person rubs crushed lice or louse feces into a break in the skin, often as a result of scratching. Louse-borne typhus may cause epidemics in refugee camps or any other situation that results in overcrowding and difficulty maintaining personal cleanliness, so that people become infested with lice and readily pass them to one another. Typhus also occurs sporadically in the highlands and cooler areas of Africa, Asia, and Central and South America. Initial symptoms include fever, chills, malaise, muscle aches, and severe headaches, followed by a rash between the fourth and seventh days of illness, at first on the upper trunk, then spreading to the rest of the body except the face, palms, and soles. Neurologic symptoms may include lethargy, delirium, or stupor progressing to coma. The drug of choice is doxycycline, which is safe and highly effective. Decontamination and delousing of all typhus patients and their clothing is essential to prevent spread. In general, travelers are not at risk for louse-borne typhus, except for health care providers and those living in intimate contact with affected populations. From the World Health Organization (WHO) Epidemic louse-borne typhus fever fact sheet West Nile Virus West Nile encephalitis is a viral infection of the brain transmitted by Culex mosquitoes, which breed in stagnant water and bite most often after dusk. Mosquitoes become infected after feeding on infected birds. Other mammals, including horses, can become infected with West Nile virus, but their role in the cycle of infection is uncertain. Recent evidence also indicates that the virus can be transmitted by transplanted organs and by blood transfusion. West Nile virus is found in Africa, Europe, West Asia, the Middle East, and North America. In countries in the temperate zone, such as the United States and Canada, the disease occurs chiefly in late summer and early fall. Further south, the disease may occur year-round. The incubation period ranges from 3 to 15 days. Most infections are mild or asymptomatic. In severe cases, the virus infects the central nervous system, leading to fever, headache, neck stiffness, confusion, lethargy, and sometimes coma and death. The virus may also cause a polio-like illness. There is no vaccine or treatment for West Nile virus infections. Mosquito protection measures are strongly advised, especially after dusk, in areas where West Nile virus has been reported. For detailed, up-to-date maps of the distribution of West Nile virus infections in the United States, go to the U.S. Geological Survey or the Centers for Disease Control. For information about the spread of West Nile in Canada, go to Health Canada. From the Centers for Disease Control (CDC) Background: Virus History and Distribution Ecology and Virology Questions and Answers Maps and Data Guidelines for clinicians From the U.K. Health Protection Agency West Nile Virus Questions and Answers Advice for those travelling to Canada and the U.S.A. From Cornell University - Center for the Environment What's going on with the West Nile Virus (superb website) From Emerging Infectious Diseases Special issue on West Nile virus From the New York Academy of Sciences West Nile Virus: Detection, Surveillance, and Control Yellow Fever Yellow fever is a life-threatening viral infection transmitted by mosquitoes in parts of Africa and South America. In urban areas, yellow fever is primarily a disease of humans and is transmitted from person to person by Aedes mosquitoes, which breed in man-made water containers, such as jars, barrels, cisterns, and discarded tires. Because Aedes mosquitoes proliferate in densely populated areas, large outbreaks may occur. However, except during epidemics, yellow fever is rare in urban settings. In the jungle, yellow fever is mainly a disease of non-human primates and is transmitted by a variety of mosquito species. Human cases occur sporadically, chiefly among those who work in the jungle, such as loggers. In the humid or semi-humid savannahs of Africa, an intermediate situation exists, wherein both monkeys and humans are infected and the disease occurs in many small villages simultaneously, but not at the levels seen in urban epidemics. This has been the pattern for most yellow fever outbreaks reported in recent years. The incubation period ranges from three to six days. Initial symptoms may include fever, chills, headache, muscle aches, backache, loss of appetite, nausea and vomiting, which usually subside in three or four days. However, after initial improvement, approximately one person in six enters a second, toxic phase characterized by recurrent fever, vomiting, listlessness, jaundice, kidney failure, and hemorrhage, leading to death in up to half of the cases. There is no treatment except for supportive care. Yellow fever vaccine (YF-VAX; Aventis Pasteur Inc.) (PDF) should be given at least ten days prior to arriving in a yellow-fever-endemic area and must be administered at an approved yellow fever vaccination center, which gives each vaccinee a fully validated International Certificate of Vaccination. The vaccine is given as a single 0.5 cc subcutaneous injection. A booster dose is recommended every 10 years for those who remain at risk. Reactions to the vaccine, which are generally mild, may include headaches, muscle aches, low-grade fevers, or discomfort at the injection site. Severe allergic reactions to yellow fever vaccine are uncommon and occur principally in those allergic to eggs. Rarely, yellow fever vaccine may lead to multiple organ system failure, similar to yellow fever caused by wild-type virus, or to neurologic illness. See the World Health Organization (PDF), the Centers for Disease Control, and Eurosurveillance for details. A recent report indicates that those with a history of thymus disease or thymectomy are at highest risk for developing multiple organ system failure and should not be given yellow fever vaccine (see Rachel Barwick Eidex, History of thymoma and yellow fever vaccination, in the Lancet, Sept. 11, 2004). Limited data also suggest that serious adverse reactions occur more commonly among the elderly and among those receiving yellow fever vaccine for the first time (see Emerging Infectious Diseases and the Centers for Disease Control). In November 2007, four laboratory-confirmed deaths were reported from yellow fever vaccine given in Peru as part of a mass immunization campaign after an earthquake. All four persons received vaccine from the same lot, manufactured by Bio-Manguinos in Brazil (widely used in South America, but not the United States). The vaccine strain caused infection of multiple organ systems, which is a known but rare complication of yellow fever vaccine. The reason why this occurred at a much higher rate than expected with this particular lot could not be determined. See the Pan-American Health Organization for further information. Because yellow fever vaccine contains live virus, it should not in general be given to those with any of the following: Age less than 6 months Thymus disorder Malignant neoplasm Primary immunodeficiency Transplantation Immunosuppressive or immunomodulatory therapies Symptomatic HIV infection or CD4 lymphocyte count less than 15% total (or less than 200/mm3 for age greater than 6 years) Allergy to vaccine components The individuals listed above should avoid traveling to areas where yellow fever is actively transmitted. Caution should be exercised before giving yellow vaccine to the following groups: Age 6-8 months Age 60 years and older Pregnancy Breastfeeding Asymptomatic HIV infection and CD4 lymphocyte count 15-24% total (or 200-499/mm3 for age greater than 6 years) Physicians considering yellow fever vaccine for pregnant women or infants between the ages of six and nine months because of special circumstances should contact the Division of Vector-Borne Infectious Diseases (telephone: 970-221-6400) or the Division of Global Migration and Quarantine (telephone: 404-498-1600) at CDC for advice. Because of the risk of encephalitis, infants less than six months of age should never be given yellow fever vaccine. Vaccination of nursing mothers should be avoided when possible. Short-term (less than two weeks) use of corticosteroids is not a contraindication to receiving yellow fever vaccine. Because yellow fever vaccine is produced in chick embryos, it should not be given to those with a history of allergy to eggs. If a country which is not infected with yellow fever requires proof of immunization and immunization is contraindicated as above, the traveler's physician should supply a waiver letter, preferably written on letterhead stationary and bearing the stamp used by official immunization centers to validate the International Certificate of Vaccination (see the Centers for Disease Control). Yellow fever vaccine may be administered with vaccines for hepatitis A, hepatitis B, typhoid (Typhim Vi), meningococcus, measles, or smallpox. There are no data regarding co-administration with rabies or Japanese encephalitis vaccines. Insect protection measures are essential when traveling to areas infected with yellow fever. From the World Health Organization Yellow fever vaccine: WHO position paper (PDF) (excellent review for physicians) Yellow fever vaccine Yellow fever (background) Yellow fever fact sheet Yellow fever vaccination certificate Safety of yellow fever vaccine Yellow fever endemic zones, Africa and Americas, 2000 Countries at risk for yellow fever and having at least one outbreak, 1985-2002 Yellow fever 1998-1999 Weekly Epidemiological Record, Vol. 75, 40, 2000. Countries at risk for yellow fever and having reported at least 1 outbreak (map) Yellow fever (PDF) (monograph by Dr. Jari Vainio and Dr. Felicity Cutts, London School of Hygiene and Tropical Medicine) From the Centers for Disease Control (CDC) Yellow Fever (Yellow Book) Map of Yellow Fever Infected Countries in Africa Map of Yellow Fever Infected Countries in the Americas Yellow Fever: Disease and Vaccine Yellow Fever Vaccine Recommendations of the Advisory Committee on Immunization Practices (ACIP), 2002 Questions and Answers About Yellow Fever Vaccine and Recent Reports of Associated Severe Illness Announcement: Revised International Certificate of Vaccination Now Available From the Pan American Health Organization (PAHO) Update on Yellow Fever in the Americas From Health Canada Yellow Fever Yellow Fever Vaccination Centres in Canada Review of adverse events reported following use of yellow fever vaccine - Canada, 1987-2000

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