Travel to Developing Countries - Infectious Diseases

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 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 January 12, 2007, 265 people had been infected with the bird flu in 10 countries. More than half of these 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. If these risks are avoided, travelers to countries with documented cases of avian flu are considered at low risk for infection. There are no travel restrictions, and preventive antiviral medications are not recommended.

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, 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.

Yellow Fever

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.