Travel to Developing Countries - Infectious Diseases

Highlights	Infectious Diseases	Resources
General Health Precautions	Travel Precautions	References
Traveler's Diarrhea	Traveling with Health Problems

Infectious Diseases

An estimated 15 - 45% of short-term travelers experience a health problem associated with their trip. And even more travelers to developing countries, including young adults, can expect to experience some health problem.

Virtually any place in the world can be reached within 36 hours, 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 between 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. Travelers are at risk both from infections transmitted from person to person and by insects (vector-borne diseases). Malaria, which is transmitted by mosquitoes, is the most widespread and infects between 300 to 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.

Common Vector-Borne Diseases
Disease	Countries of Infection	Severity and Symptoms	Treatment and Prevention
Malaria Parasite transmitted by anopheles mosquitoes.	The world's number one infection. 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 to 30 days following exposure. Symptoms can occur forup 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. There is widespread resistance to standardanti-malaria drugssuch as chloroquine or primaquine. Alternative drugs include quinine, atovaquone/proguanil, or derivatives of artemisinin. Prevention: Many parasites are resistant to chloroquine. Alternative drugs include atovaquone-proguanil (Malarone), mefloquine (Lariam), 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.
Yellow Fever Arbovirus transmitted by mosquito.	Nearly all cases occurin 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 toendemic areas. Vaccinations requiredfor entry intocertain countries. Vaccine not usually recommended for pregnant women, infants, 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.	Treatment: Pentamidine and suramin for early stages. Rimantadine under investigation. Melarsoprol and eflornithine for late stage. Nifurtimox being tested. Prevention: Flies attracted to dark, contrasting colors. Flies not affected by insect repellents.
Chagas' disease(American Trypanosomiasis) Parasite transmitted by infected Reduviid bugs.	South and Central America	Symptoms range from acute to chronic and may include: swelling of the eye, fatigue, fever, rash, diarrhea, vomiting, swelling of internal organs, heart problems.	Treatment: Nitrofurans foracute attacks. Benzimidazole for recurrence. Prevention: Avoid buildings made of mud, adobe, and thatch, which can harbor the reduviid bug.
Dengue Fever Virus transmitted by mosquitoes.	Can occur in any tropical or subtropical country. Greater risk in cities than in the country.	High fever, severe headache, vomiting, muscle and joint pain, occasionally rash on trunk and upper arms. Disease ends abruptly after3 to6 days. Patients usually recover, but fatal hemorrhage can occur.	Treatment: Blood transfusions, fluids, pain killers (aspirin, ibuprofen, or other NSAIDs should not be used). Prevention: Vaccine is under investigation.
Encephalitis 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. 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.
Leishmaniasis Parasitic disease transmitted by a sand fly.	Central America, South America, Asia, and the Middle East.	Skin sores and mouth and nose ulcers, sometimes disfiguring. Organ infection can involve spleen, liver, and bone marrow.	Treatment: Antimony-containing drugs (meglumine antimonate) for organ infection; also pentamide, amphotericin. Fluconazole effective for skin sores. Prevention:No vaccine available.
Plague 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. Medical 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.
Schistosomiasis Schistosoma parasite lives 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.	Fever, flu-like symptoms, rash, respiratory. Respiratory symptoms. Can be mild, but also can damage liver, kidneys bladder, intestines, or central nervous system.	Treatment: Praziquantel (Biltricide). Reports of resistance have raised concern. Prevention: Do not swim or wade in fresh water.

Nonvector-Borne Bacterial or Viral Infectious Diseases Encountered by Travelers
Disease	Countries of Infection	Severity and Symptoms	Treatment and Prevention
Cholera Bacterial infection transmitted in contaminated water or food.	Outbreaks occur in many developing countries with poor sanitation. More common in warm months.	Diarrhea and vomiting lasting one to three days. In severe cases, profound dehydration can be fatal.	Treatment: Tetracycline usually effective within 48 hours. Consume as much purified water as possible. Prevention: Recently developed vaccines (Dukoral, Mutacol) are more effective than previous ones. Not recommended or available, however, in the US.
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 andlow-grade fever that increases every day for a week or more. In the second stage, fever stabilizes. "Pea soup" diarrhea or constipation can develop. Untreated, disease can last up to4 weeks and is fatal in 10% of such cases.	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 travelersvisiting high-risk countries for more than four weeks.
Hepatitis A Viral infection transmitted in contaminated water or food.	Worldwide. Highest risk in developing nations, particularly where 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 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: 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 vaccination4 weeks before travel. Immune globulin used for children under2 years.
Hepatitis B Viral infection transmitted through contaminated blood. 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 appear4 to 24 weeks 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) both hepatitis A and B. Vaccination recommended for all children and travelers to developing countries.
Poliomyelitis (Polio) 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 andcan be fatal.	Treatment: Treatments only for symptoms. Prevention: Universal immunization with vaccine required. Booster needed for adults traveling to developing country. Inactivated polio vaccine (eIPV) preferred.
Meningococcal Disease 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. Particularly dangerous for children.	Treatment: Early administration of antibiotics is essential. Prevention: Vaccines for travelers in the meningitis belt and other areas with outbreaks.
Leptospirosis Bacteria excreted in the urine of animals.	Contracted from swimming or bathing in fresh water. Tropical and subtropical countries pose highest risk.	Flu-like symptoms, diarrhea, and eye inflammation. In severe cases, 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. As of 2005, SARS not active in any parts of the world.	Serious form of atypical 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. Vaccine in development.
Tuberculosis Bacterial infection spread through air, typically from long-term exposure to infected person. 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.	Treatment: Isoniazid or2 months of rifampin plus pyrazinamide. Prevention: BCG vaccine available for children in developing countries. Not routinely used for travelers. Consider screening children who return from developing countries.
Rabies Virustransmitted 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: Supportive treatments only. Prevention: Vaccine for travelers who intend to work with animals or spend time in rural areas for more than a month in countries where the rabies virus is endemic. Immunization does not eliminate the need for treatment after exposure to the virus, but it does shorten the course of the disease.