Background: Millions of Americans visit developing countries each year, however, little is known about their health during travel. This study describes health problems in a large cohort of American travelers during and after their trip.

Method: A 2-year survey of 784 travelers (95% follow-up) was conducted for persons traveling for ≥ 90 days. At the pretravel visit, travelers were given a postcard to record adverse health events. Following travel, standardized telephone interviews were performed for any positive responses, or if the card was not returned. All travelers were contacted 2 months after return to determine late occurring illness and compliance with antimalarials.

Results: Travelers had a mean age of 44 years, a median duration of 19 days, and visited 123 countries. An illness was reported by 64% (1.6 illnesses per traveler). Ill travelers were more often female, and traveled longer than those who were not ill; depending upon destination, each day of travel increased by 3 to 4% the chance of becoming ill. Diarrhea was most common, occurring in 46%; 34% met a strict definition for traveler's diarrhea. Respiratory illness occurred in 26%, skin disorders in 8%, acute mountain sickness in 6%, motion sickness in 5%, accidents and injuries in 5%, and isolated febrile episodes in 3%. Medical care was sought by 8% of all travelers and 12% of those reporting illness. On return, 26% of travelers were ill, 56% of whom became ill after return. Diarrhea, respiratory illness, skin disorders, and febrile syndromes were most common, and 46% of those who were ill sought medical care. Complete compliance with antimalarials was 80%. Noncompliant individuals usually discontinued medications on return. Side effects were reported by 4% of those taking chloroquine, 11% of those taking chloroquine plus proguanil, and 14% of those taking mefloquine, with half of these neuropsychiatric. The incidence of documented malaria was 3.8 cases per 1,000 travelers.

Conclusions: Many travelers experience adverse health events during and after travel to the developing world. Attention to the prevention and therapy of traveler's diarrhea, prophylaxis of malaria, management of respiratory illness, personal safety, and access to medical care during travel, and, recognition of clinical syndromes after return, will help to improve the traveler's health.