Travel to Developing Countries

Common Vector-Borne Diseases

Disease

Countries of Infection

Severity and Symptoms

Treatment and Medical Prevention*

Malaria

Parasite transmitted by anopheles mosquitoes.

The world's number one infection. Found in every tropical or subtropical country in the world and in some parts of Eastern Europe. In one 2001 Australian study, the risk for travelers was highest in the Pacific region and sub-Saharan Africa (1 in 50 to 1 in 1000), followed by the Indian subcontinent (1 in 1000 to 1 in 12,000); it was lowest in Southeast Asia and South America. (There is no risk in North America, Western Europe, New Zealand, or Australia.) Note: Pregnant women are at higher than average risk for malaria, particularly in the second trimester through the early postpartum period.

Initial symptoms are flu-like, also possibly nausea and vomiting. Yellowish skin. Without prompt treatment, can be fatal. Typically develops 10 days to a month following exposure. Symptoms can occur up to a year or more, however, even after careful preventive measures. People who have been in countries with malaria should report fever or other symptoms plus travel information to their physician even months after they return.

Treatment: Immediate treatment is important. Primary difficulty is widespread resistance to standard agents.

Chloroquine in areas where resistance to this drug is low, usually followed by primaquine.

Quinine (usually in combination with clindamycin or tetracycline) in chloroquine-resistant regions.

Atovaquone/proguanil (Malarone) in chloroquine-resistant areas if it has not been used for prevention.

Derivatives of artemisinin (qinghaosu) in combination with other agents may delay resistance. Example is artemether/lumefantrine (Coartem). Recently added to WHO essential medicines list. Another promising combination is artesunate and amodiaquine.

All have significant side effects.

Emergency Self-Treatment: If no help is available for 24 hours, self treatment may be necessary:

Typically, single dose of three Fansidar (a combination of pyrimethamine and sulfadoxine) if symptoms develop while traveling, but only if medical care is not available. Continuous use can cause severe and even life-threatening reactions. Not for people allergic to sulfa drugs.

Malarone may prove to be useful in these cases.

Medical Prevention: * Chloroquine (Aralen). Standard preventive drug, Resistant parasites limiting use in many countries.

The following are agents used in countries with parasites resistant to chloroquine:

Combination of atovaquone-proguanil (Malarone). Currently the best choice. Effective and better tolerated than other standard agents, including in children and elderly.

Mefloquine (Lariam). Standard agent recommended by US and recommended by UK for prolonged stay in most regions and Africa and specific areas in SE Asia. Significant side effects, including risk for serious mental disturbances.

Doxycycline. Can cause photosensitivity. Should not be used by small children or pregnant women.

Regimen of weekly chloroquine and daily proguanil (Paludrine). Available outside the US. Safe for pregnant women. Has significant side effects. Less effective than standard agents.

Other agents, including tafenoquine and vaccines are under investigation.

Yellow Fever

An arbovirus transmitted by mosquito.

Nearly all cases in African countries occur near the equator and in tropical parts of South America. Most cases in moist savanna areas of West and Central Africa in rainy season. Occasional outbreaks in cities and villages in Africa. Lesser extent in any jungle regions. Recent outbreaks in Brazil in South America and Senegal and Guinea in Africa.

Initial symptoms are usually mild and include headache, fatigue, fever, nausea, vomiting, and constipation. Body temperature usually returns to normal after seven to eight days. Severe symptoms may develop and include bleeding under the skin or from mucous membranes, vomiting material resembling coffee grounds, jaundice (thus, the name, yellow fever). Fatal in 23% of cases in which symptoms are severe. People who recover are immune for life.

Treatment: No exact treatment regimen for symptoms.

Medical Prevention: * Yellow Fever is rare in travelers, but vaccination is recommended before traveling to problem areas. Vaccinations required in African countries near the equator, in tropical parts of South America, and sometimes when outbreaks occur in other areas, or when travelers come from infected areas. Vaccine not usually recommended for pregnant women, infants, immunocompromised patients, or possibly for elderly people. Nevertheless, if the risk for yellow fever is significant, the vaccination may be warranted in these people.

Less Common Vector-Borne Diseases

Disease and Method of Transmission

Countries of Infection

Severity and Symptoms

Treatment and Medical 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.

Medical Prevention: Flies attracted to moving vehicles and 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, and swelling of internal organs to heart problems in chronic stage.

Treatment: Nitrofurans (e.g., Nifurtimox) and similar agents for short-term activity. Benzimidazole for recurrence. A number of agents under investigation.

Medical 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. A large dengue epidemic currently reported spreading across Asia and the Pacific, including Hawaii and Philippines. Large outbreak also has been reported in Brazil.

High fever, severe headache, muscle and joint pain, and sometimes vomiting and rash on trunk and upper arms. Disease ends abruptly after three to six days. Patients usually recover, but fatal hemorrhage, can occur and be fatal. Fortunately, this is rare and more likely in someone with a second infection.

Treatment: Treatments include blood transfusions, plenty of fluids, pain killers (aspirin, ibuprofen, or other so-called NSAIDs should not be used).

Medical Prevention: * Vaccine is under investigation.

Encephalitis

A number of different viruses carried by mosquitoes.

Worldwide risk although higher in some regions than others. Overseas, high-risk areas include China and Korea, India, Southeast Asia. Low frequency in Japan, Taiwan, Singapore, Hong Kong, and eastern Russia.

Severity depends on the virus. Can be mild to life threatening, and can 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.

Medical 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 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 B. Fluconazole effective for skin sores.

Medical Prevention:* No vaccines.

Plague

Bacteria carried by rodents and transmitted by fleas.

Most plagues are transmitted by handling infected animals. An exception is the Indian pneumonic plague, which can be passed in the air, although the risk of picking it up is very low. 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. Risk to travelers is very small.

Swollen and tender lymph nodes, fever, chills, headache, malaise, prostration, and gastrointestinal symptoms. Can be fatal without treatment.

Treatment: Antibiotics.

Medical Prevention: * Travelers should wear insect repellents and avoid handling any animals. Adults traveling to countries with plague outbreak may consider taking preventive antibiotics like tetracycline or doxycycline. 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-Sahara Africa is a particular hazard for schistosomiasis in travelers. Other countries: Brazil, Puerto Rico, St. Lucia (an island in the West Indies), Egypt, the sub-Saharan part of Africa, Southern China, the Philippines, and Southeast Asia.

Causes fever, flu-like symptom, rash. Respiratory symptoms.

Can be mild, but also can damage liver, kidneys bladder, intestines, or central nervous system.

Treatment: The current treatment is praziquantel (Biltricide). Reports of resistance to this agent have raised concern.

Medical Prevention:* Do not swim or wade in fresh water and avoid contact with animals. Vaccine under investigation.

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 developing countries with poor sanitation. More common in warm months. Specific outbreaks in 2002 have been reported in Somalia, Malawi, and Republic of Congo. Other recent outbreaks reported in South America.

Usually mild 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, which provided little protection. 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. Common in India, Pakistan, and neighboring regions, North and West Africa (except Tunisia), and Peru.

The first symptoms include flu-like symptoms and classic stepladder low-grade fever that increases every day for a week or more. Temperature highest in the evenings. Possible pink rash across the abdomen that fades.

In the second stage, fever stabilizes. Pea soup diarrhea or constipation can develop. Untreated, disease can last up to four weeks and is fatal in 10% of such cases. Death is rare in travelers.

Treatment: Antibiotics essential and can cure the disease. Ciprofloxacin is antibiotic of choice. Fluid replacement and nutrition maintenance is critical.

Prevention: Vaccinations recommended for travelers to high-risk countries staying for more than four weeks.

Oral vaccines include: (Ty21a, Vivotif,). The oral vaccines are not effective against parathyroid fever.

One-shot vaccine (Typhim Vi). Can be taken as early as two weeks before travel. Vi-rEPA is a newer injected vaccine that is safe in children and may be more effective-than other vaccines to date.

No vaccine is 100% effective, and the response tends to be lower in older people.

Anyone exposed should keep hands very clean and avoid preparing food for others.

Patients who have contracted typhoid fever may still carry it when they return, even if their symptoms have been relieved. They should continue to take strict precautions against passing it on until a physician has determined that the bacteria have been eliminated. They should abstain from sexual contact until they finish a full course of antibiotics, about two to three 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. Stop all medications except as approved by physician. Abstain from alcohol and sexual contact. Avoid dehydration and becoming over tired. 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 vaccination four weeks before travel.

Immune globulin used for children under two 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 appear four to 24 weeks but can also occur long after the initial infection. Often no symptoms, but even patients with symptoms can remain chronically infected with the virus.

Treatment: Treatment of symptoms for acute hepatitis B.

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, and most of the new independent countries of the former Soviet Union, including Albania. In 2001, cases reported Haiti, and the Dominican Republic.

Symptoms in small children can be mild and flu-like. More likely to be serious in older children and adults. In such cases symptoms include severe fever, headache, stiff neck and back, deep muscle pain, or odd sensations. Can lead to paralysis, sometimes only in certain muscles. Can be fatal.

Treatment: Treatments are available only for symptoms.

Prevention: Universal immunization with vaccine required. Booster needed for adults traveling to developing country. Inactivated polio vaccine (eIPV) preferred. Travelers not previously immunized should receive three doses of injectable vaccine at intervals of one to three months. If departure is imminent, travelers should have a single dose at home and booster shots at appropriate intervals abroad.

Meningococcal Disease

Bacterial infection in the fluid and membranes covering the brain and spinal cord. It is spread through coughs, sneezes.

The so-called meningitis belt (countries extending across sub-Sahara Africa from Nigeria to Somalia). Outbreaks in the belt and in Burkina Faso and Niger have been reported in 2003.

Fever, chills, headache, stiff neck, rash caused by bleeding into the skin, and vomiting. Can also cause pneumonia. It is particularly dangerous for children.

Treatment: Antibiotics. Early administration is life saving.

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 contaminated water. Travelers who engage in water sports, such as rafting, are at higher risk. Tropical and subtropical countries pose highest risk.

Flu-like symptoms, diarrhea, and eye inflammation. In severe cases, it can cause 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 a new coronavirus. Spread by infected droplets from coughing, sneezing. Can be transmitted on objects. Found in feces.

First identified in China, where most cases still occur. Cases have now occurred worldwide, although it is under control in most nations.

Serious form of atypical pneumonia, resulting in acute respiratory distress and sometimes death. The hallmark symptoms are fever greater than 100.4 F (38.0 C) and cough, difficulty breathing, or other respiratory symptoms.

Treatment: Anti-viral medications and high doses of steroids being tried in Asia without evidence for efficacy to date. Supportive care.

Prevention: Intensive public health programs to contain epidemics.

Personal preventive measures include good hygiene, especially careful and frequent hand washing with soap and water.

Tuberculosis

Bacterial infection spread through air, typically from long-term exposure to infected person. Also has been passed in unpasteurized milk.

A few reports of TB in airline passengers exposed to TB during long flight. High rates of TB are found in Mexico, China, Hong Kong, Taiwan, Central America, Philippines, Vietnam, India, Haiti, and South Korea.

Coughing, weight loss, fever, night sweats.

Treatment: Isoniazid or two 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

Viral infection. Virus passes 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.