Infectious diseases of travelers and immigrants.

Many tropical and other unusual infections can occur in travelers or among foreign-born persons who have emigrated to the United States. The approach to the differential diagnosis includes considering the patient's geographic history, dates of travel, and clinical presentation, along with the geographic distribution and possible incubation periods of suspected pathogens. Important considerations include malaria, typhoid fever, rickettsial disease, dengue, brucellosis, tuberculosis, and leptospirosis. Traveler's diarrhea and dysentery are also common.