A common problem of travelers, either on the trip or after they return, is a febrile illness, usually caused by infection. Fever in a traveler is often caused by disease not specifically related to travel and just as likely to occur at home. These include, among others, such cosmopolitan causes as common cold, sinusitus, influenza, tonsillitis, pyelonephritis, and bacterial or mycoplasmal pneumonia. However, the subject of this chapter is more exotic diseases acquired in developing countries (See Table 115.1). With the great increase in volume and speed of travel between developed and developing countries, physicians in the United States and other developed countries are seeing more patients with exotic tropical infections. Some of these infections are widespread in developing countries, and others are limited to small areas. Thus knowledge of geographic distribution may be essential to the correct diagnosis.

The most common tropical fevers in travelers are malaria, enteric fever, hepatitis, amebic liver abscess, and rickettsial and arboviral infections.

MALARIA

A febrile traveler returning from an area of endemic malaria must first and foremost be evaluated for malaria. Most malarial infections occur in travelers who have had inappropriate, irregular, or no chemoprophylaxis. However, all febrile travelers from a malarious area must be examined for malaria because no chemoprophylactic regimen can be considered fully protective. Potentially lethal falciparum malaria usually occurs within 4 weeks after leaving a malarious area.