Fever in travelers returning from tropical areas: prospective observational study of 613 cases hospitalised in Marseilles, France, 1999-2003.

Background: Febrile travelers may pose a diagnostic challenge for Western physicians who are frequently involved in the assessment of these patients but unfamiliar with tropical diseases. Evaluation of this situation requires an understanding of the common etiologies, which are associated with the demographics of travelers and the destinations.

Methods: We conducted a 5-year prospective observational study on the etiologies of fever in travelers returning from the tropics admitted to the infectious and tropical diseases unit of a university teaching hospital in Marseilles, France.

Results: A total of 613 patients were enrolled, including 364 migrants (59.4%), 126 travelers (20.6%), 37 visitors (6%), 24 expatriates (3.9%), and 62 patients (10.1%) who could not be classified. Malaria was the most common diagnosis (75.2%), with most cases (62%) acquired by migrants from the Comoros archipelago and who had traveled to these islands to visit friends and relatives. Agents of food-borne and water-borne infections (3.9%) and respiratory tract infections (3.4%) were also frequently identified as the cause of fever. Other infections included emerging diseases such as gnathostomiasis, hepatitis E infection and rickettsial diseases, as well as common infections or exotic diseases.

Conclusions: Although we have identified here various causes of imported fever, 8.2% of the fevers remained unexplained. An improved approach to diagnosis may allow for the discovery of new diseases in travelers in the future.