Cholera; Dengue fever; Traveler's diarrhea; Malaria; Schistosomiasis; Typhoid; Yellow fever
An estimated 15 - 45% of short-term travelers experience a health problem associated with their trip. This percentage is higher in travelers to developing countries.
A traveler can reach virtually any place in the world within 36 hours, which is less than the incubation period for most infectious diseases. The ease with which people see the world has dramatically increased the number of foreign travelers. Respiratory infections, such as influenza and colds, develop in 10 - 25% of travelers. Women traveling to the tropics are at high risk for urinary tract infections.
Even worse, doctors in Western countries are now seeing infectious diseases never before encountered in their regions. Travelers are at risk from infections transmitted among people, as well as those transmitted by insects (vector-borne diseases). Malaria, which is transmitted by mosquitoes, is the most widespread vector-borne disease, and infects 300 - 500 million people world wide annually. Between 10,000 and 30,000 of these cases occur in travelers. Anyone traveling to high-risk countries should take precautions.
A Word about Bird Flu
Avian influenza type A (also known as bird flu and avian flu) is a disease causing death in more than 50% of infected persons. The virus (H5N1) is common in birds, but often does not make them appear ill. As of December 16, 2008, 391 people had been infected with the bird flu in 15 countries. Of these, 247 people have died, according to the World Health Organization. No cases have been seen in the United States. Risk factors for infection include close contact with caged birds or poultry (chickens, ducks, and turkeys), eating undercooked poultry products, and contact with poultry feces. To date, there are no documented cases of transmission of bird flu from one human to another. If they avoid these risk factors, travelers to countries with documented cases of avian flu are considered at low risk for infection. There are no travel restrictions associated with avian influenza, and preventive antiviral medications are not recommended.
Common Vector-Borne Diseases
Countries of Infection
Severity and Symptoms
Treatment and Prevention
Parasite transmitted by anopheles mosquitoes.
The world's number one infection, and nearly entirely preventable. Found in every tropical or subtropical country in the world.
Initial symptoms are flu-like, with possible nausea and vomiting. The skin may appear yellow. Without prompt treatment, can be fatal. Typically develops 10 - 30 days following exposure. Symptoms can occur for up to a year or more. People who have been in malarial countries should report fever or other symptoms plus travel information to their doctor even months after they return.
Treatment: Immediate treatment is important, but the appropriate treatment depends on the traveler's destination. There is widespread resistance to standard anti-malaria drugs such as chloroquine or primaquine. Alternative drugs include quinine, atovaquone/proguanil (Malarone), doxycycline, mefloquine (Lariam), hydrochloroquine, or derivatives of artemisinin.
Prevention: Many parasites are resistant to chloroquine. Alternative drugs include atovaquone-proguanil, mefloquine, and doxycycline. Malarone causes fewer side effects than other drugs. Lariam should not be used by people with history of psychiatric disorders. Doxycycline can cause photosensitivity. Prevention should focus on minimizing exposure to mosquitoes and "mosquito-proofing" living and sleeping accommodations.
Arbovirus transmitted by mosquito.
Nearly all cases occur in African countries near the equator and in tropical parts of South America.
Initial symptoms are usually flu-like and include headache, fatigue, fever, nausea, vomiting, and constipation. Severe symptoms include jaundice and hemorrhagic fever. Fatal in 23% of cases with severe symptoms. People who recover are immune for life.
Treatment: No exact treatment regimen for symptoms.
Prevention:Vaccination recommended before traveling to endemic areas. Vaccinations required for entry into certain countries. Vaccine not usually recommended for pregnant women, infants, nursing mothers, immunocompromised patients, or patients with history of thymus gland disease.
Less Common Vector-Borne Diseases
Disease and Method of Transmission
Countries of Infection
Severity and Symptoms
Treatment and Prevention
African sleeping sickness (African Trypanosomiasis)
Parasite transmitted by tsetse fly bite.
Rural Africa, between latitudes 15 degrees N and 20 degrees S.
Symptoms may include fever, chills, headache, fluid accumulation in hands and feet, sleepiness, lethargy, and convulsions. Without treatment, the sickness is fatal.
Treatment: Pentamidine and suramin for early stages. Rimantadine under investigation. Melarsoprol and eflornithine for second stage. Nifurtimox being tested.
Prevention: Flies are attracted to dark, contrasting colors. Flies are not affected by insect repellents.
Chagas' disease (American Trypanosomiasis)
Parasite transmitted by infected Reduviid bugs.
South and Central America
In the acute stage, symptoms can include a skin lesion, fever, loss of appetite, lymph node swelling, spleen and liver enlargement, and inflammation of the walls of the heart. Symptoms that may occur years or decades later include dementia, weakening of the heart, dilation of digestive tract, weight loss.
Treatment: Benznidazole and nifurtimox are usually only effective in acute attacks. Benzimidazole is also used for recurrences. Antiparasitic treatment may be recommended.
Prevention: Avoid buildings made of mud, adobe, and thatch, which can harbor the reduviid bug.
Virus transmitted by mosquitoes.
Can occur in any tropical or subtropical country. Greater risk in cities than in the country. In 2005, dengue was comparable to malaria in global distribution.
High fever, severe headache, vomiting, backache, eye pain, muscle and joint pain, occasionally rash on trunk and upper arms. Disease ends abruptly after 2 - 7 days. Patients usually recover, but internal bleeding and fatal hemorrhage can occur. This stage of the disease is called dengue hemorrhagic fever.
Treatment: Blood transfusions, fluids, pain killers. (Aspirin, ibuprofen, or other NSAIDs should not be used, but acetaminophen is okay.)
Prevention: No vaccine has been developed. Prevention requires protection against mosquito bites, particularly in the daytime.
A number of different viruses carried by mosquitoes.
Worldwide risk although higher in some regions than others. High-risk areas include China and Korea, India, Southeast Asia.
Can be mild to life threatening. Brain swelling produces symptoms include headache, neck stiffness, confusion, irritability, fever, weakness, dizziness, tremors, seizures, and paralysis. Serious symptoms include lethargy, delirium, coma, and even death.
Treatment: Symptomatic treatment only.
Prevention: The vaccine (Je-Vax) for Japanese encephalitis is recommended only if travelers are visiting rural areas in high-risk Asian countries for more than 30 days.
Parasitic disease transmitted by a sand fly.
Found in 88 countries around the world.
Most common forms cause skin sores and mouth and nose ulcers, sometimes disfiguring. Organ infection can involve spleen, liver, and bone marrow.
Treatment: Antimony-containing drugs (meglumine antimonate, Glucantime; sodium stibogluconate, Pentostam) for organ infection; also pentamide isethionate (Pentam 300), amphotericin B (Fungizole). Fluconazole is also effective for skin sores.
Prevention: No vaccine available.
Bacteria carried by rodents and transmitted by fleas.
Most plagues are transmitted by handling infected animals. However, the Indian pneumonic plague is airborne. Human plague reported in recent years in Africa, South East Asia, parts of South American and the US. Recently been reported in India, Vietnam and Zambia. Risk generally in rural mountainous areas.
Swollen and tender lymph nodes, fever, chills, headache, malaise, prostration, and gastrointestinal symptoms. Can be fatal without treatment.
Treatment: Antibiotics, particularly streptomycin. Alternatives include gentamicin, tetracyclines, chloramphenicol.
Prevention: Use insect repellents and avoid handling any animals. Adults traveling to countries with plague outbreak may consider preventive antibiotics. Children may take sulfonamides. Vaccine under investigation.
Schistosoma parasitic worms live off a specific snail in fresh water contaminated with feces.
Lake swimming in sub-Saharan Africa is a particular hazard for schistosomiasis in travelers. Other countries: Brazil, Puerto Rico, St. Lucia, Egypt, Southern China, the Philippines, and Southeast Asia.
Within days, itchy skin or rash. Within 1 - 2 months, fever chills, cough, muscle aches.
Can be mild, but also can damage liver, kidneys bladder, intestines, or central nervous system.
Treatment: Praziquantel (Biltricide) or oxamniquine (Vansil). Reports of resistance have raised concern.
Prevention: Do not swim or wade in fresh water in countries where schistosomiasis occurs. Boil drinking water for 1 minute. Heat bath water to 150 °F for 5 minutes.
Nonvector-Borne Bacterial or Viral Infectious Diseases Encountered by Travelers
Countries of Infection
Severity and Symptoms
Treatment and Prevention
Bacterial infection transmitted in contaminated water or food.
Outbreaks occur in many developing countries with poor sanitation. More common in warm months.
Perfuse, watery diarrhea, abdominal pain, and vomiting lasting 1 - 3 days. In severe cases, profound dehydration can be fatal.
Treatment: Tetracycline and oral hydration salts usually effective within 48 hours. Consume as much purified water as possible.
Prevention: Risk to travelers is considered low, and the vaccines are not produced in the U.S. or required for international travel.
Typhoid Fever and Parathyroid Fever(Enteric Fever)
Bacterial infection (salmonella typhi) in contaminated water or food. Can be spread by flies.
Can occur in any region where food or water is contaminated. Outbreaks common after natural disasters in poor countries. Tends to occur in urban areas.
Initial flu-like symptoms and low-grade fever that increases every day for a week or more. In the second stage, fever stabilizes at 103 - 104 °F. "Pea soup" diarrhea or constipation can develop. Untreated, disease can last up to 4 weeks and is fatal in 10% of patients. After symptoms end, the patient is still infectious.
Treatment: Antibiotics essential. Ciprofloxacin is antibiotic of choice. Fluid replacement and nutrition maintenance is critical. Even when symptoms have resolved, patients may be contagious until bacteria is eliminated.
Prevention: Vaccinations recommended for travelers visiting high-risk countries for more than four weeks. Drink bottled water. Take same precautions as for traveler's diarrhea.
Viral infection transmitted in contaminated water or food.
Worldwide. Highest risk in developing nations, particularly where sanitation is poor and cholera and typhoid are prevalent.
Nausea and vomiting, decreased appetite, itching, extreme fatigue, jaundice, fever, and abdominal pain. Serious complications are rare, but recovery may take 6 - 9 months.
Treatment: No specific treatment for acute hepatitis. Abstain from alcohol and sexual contact. Avoid dehydration. Keep own eating and cooking utensils separate from others.
Prevention: Wash hands after using the bathroom. Two vaccines are available as well as combination vaccine for hepatitis A and B. Vaccination recommended for travel to any nation where risk is intermediate or high. Immunity from vaccine may develop more slowly in elderly people. CDC recommends vaccination 4 weeks before travel. HepA vaccine is recommended for all children at age 1.
Viral infection transmitted through contaminated blood, or through sex or sharing needles with an infected person. Can be passed from cuts, scrapes, and other breaks in the skin.
Common in Southeast Asia, Africa, the Middle East, islands of the South and Western Pacific, the Amazon region of South America, and the Mediterranean.
Flu-like mild symptoms. Sometimes rash, aching in joints. Symptoms usually appear 4 - 24 weeks after exposure but can occur long after initial infection. Often no symptoms, but even patients with symptoms can remain chronically infected with the virus.
Treatment: Treatment of symptoms.
Prevention: Several vaccines are now available, including a combination vaccine (Twinrix) for hepatitis A and B. Vaccination recommended for all children and for travelers to developing countries.
Viral infection transmitted in contaminated water or food.
Most developing countries in Africa, Asia, Latin American, the Middle East, India and neighboring regions, Eastern Europe and Central Asia.
Symptoms in small children can be mild and flu-like. More likely to be serious in older children and adults. Symptoms include severe fever, headache, stiff neck and back, deep muscle pain. Can lead to paralysis and can be fatal.
Treatment: Treatments only for symptoms.
Prevention: Universal immunization with vaccine required. All babies should receive vaccination as part of standard vaccine schedule, with booster at 4 -6 years of age. Booster needed for adults traveling to developing country. Inactivated polio vaccine (IPV) is used.
Bacterial infection in the fluid and membranes covering the brain and spinal cord. Spread through coughs, sneezes.
The so-called meningitis belt (countries extending across sub-Sahara Africa from Nigeria to Somalia).
Fever, chills, headache, stiff neck, rash caused by bleeding into the skin, and vomiting. Can also cause pneumonia and loss of limbs. Particularly dangerous for children.
Treatment: Early administration of antibiotics is essential.
Prevention: Vaccines for travelers in the meningitis belt and other areas with outbreaks. Vaccine now recommended as standard for all children 11-12 years of age and entering college freshmen living in dorms and not previously vaccinated.
Exposure to bacteria from the urine of animals by swimming or bathing in contaminated fresh water.
Tropical and subtropical countries pose highest risk.
High fever, severe headache, diarrhea, and eye inflammation. In severe cases, can develop internal bleeding and liver and kidney damage.
Treatment: Antibiotics (as early as possible).
Prevention: Avoid water activities where leptospirosis occurs.
Severe Acute Respiratory Syndrome (SARS)
Respiratory infection caused by coronavirus. Spread by infected droplets from coughing, sneezing.
First identified in China in 2003, not currently active in any parts of the world.
Serious form of unusual pneumonia, resulting in acute respiratory distress. Hallmark symptoms are high fever, cough, difficulty breathing, or other respiratory symptoms.
Treatment: Supportive care.
Prevention: Practice good hygiene, avoid contact with SARS patients. Vaccine in development.
Bacterial infection spread through air by coughing or sneezing. Also has been passed in unpasteurized milk.
High rates found in Africa, Asia, Central and Eastern Europe (including former Soviet Union), Latin America.
Coughing, weight loss, fever, night sweats. Can spread from lungs to central nervous system, genitourinary system, bones and joints. Ninety percent of infected people have no symptoms.
Treatment: Multiple drugs for 6 months or longer.
Prevention: BCG vaccine available for children in developing countries. Not routinely used for travelers. Consider screening children who return from developing countries. Isoniazid or other medications can prevent acute disease in people who are infected but not ill.
Virus transmitted from exposure to saliva from an infected animal (even from licking). Dogs are main carriers but all mammals susceptible.
Worldwide except Antarctica (some specific countries are rabies free).
Disease is nearly always fatal once symptoms develop.
Treatment: Immunoglobulins after bites, vaccine if not previously vaccinated (previously vaccinated travelers only require booster vaccine, but no immunoglobulins). Clean the wound with soap and water, and iodine if possible, immediately after bite. If symptoms develop, supportive treatments only.
Prevention: Vaccine is available and recommended for travelers who intend to work with animals or are likely to come in contact with animals in countries where the rabies virus is common. Immunization does not eliminate the need for treatment after exposure to the virus, but it does shorten the course of the disease.
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