Background

Approximately 8 percent of travelers to developing countries require medical care during or after travel. However, the current understanding of morbidity profiles among ill-returned travelers is based on limited data from the 1980s. The GeoSentinel sites, specialized travel or tropical-medicine clinics on six continents, contributed clinician-based sentinel surveillance data for 17,353 ill-returned travelers. The study aimed to compare the frequency of each diagnosis among travelers returning from six developing regions worldwide.

Methods

Data were collected from June 1996 through August 2004. The characteristics of each patient were documented, and the diagnoses were categorized into 21 major syndrome categories. By analyzing the data, the study aimed to verify the assumption that the travel destination is associated with the probability of each diagnosis among travelers returning from the developing world.

Overall Morbidity

The median travel duration ranged from 14 days for the Caribbean to 35 days for South America. Most patients (64%) were seen within a month after travel, while 10% had indolent diseases or diseases with a long incubation period and were not seen until more than six months after the journey.

Destination Analysis

Significant differences in proportionate morbidity were seen among the travel regions for 16 of the 21 syndrome categories. In particular, systemic febrile illness was found disproportionately among patients presenting to GeoSentinel sites after traveling to sub-Saharan Africa or Southeast Asia, and acute diarrhea among those presenting after traveling to south-central Asia.

Regional Morbidity According to Specific Diagnosis

Malaria was the most frequent cause of systemic febrile illness among travelers from every region. Travelers with dengue presented more frequently than malaria for every area except sub-Saharan Africa and Central America. Rickettsial infections, primarily tick-borne spotted fever, appeared almost exclusively among travelers returning from sub-Saharan Africa, and typhoid fever was a primary contributor to systemic febrile illness among travelers from south-central Asia.

For all regions except Southeast Asia, parasite-induced diarrhea was more common among ill-returned travelers than bacterial diarrhea. Insect bites were the most common cause of dermatologic problems, followed by cutaneous larva migrans, allergic reactions, and skin abscesses. Leishmaniasis was primarily found among patients who had traveled to South America or, to a lesser extent, Central America.

Rare Diagnoses

Rare or exotic diagnoses, such as Ebola virus disease, Japanese encephalitis, and yellow fever, did not occur among the 17,353 travelers whose data were analyzed in this study. However, some rare diagnoses occurred only once among travelers, such as Angiostrongylus cantonensis infestation and hantavirus infection.

Proportionate Morbidity According to Region

Travel destinations are associated with the probability of the diagnosis of certain diseases. These destination-specific differences can guide diagnostic approaches and empiric therapies. This information can be helpful for health providers in assessing the health risks faced by travelers to developing countries and guiding post-travel diagnosis and empiric treatment. It can also aid in prioritizing pretravel intervention strategies.