Malaria and Use of Prevention Measures Among United States Travelers

Summary

Each year between 7 and 8 million United States citizens travel to countries with malaria. The spread of drug-resistant Plasmodium falciparum malaria and the limited array of safe and effective drugs for prophylaxis have resulted in an increased risk of infection for United States travelers to many of these countries. This risk is high (1 per 50 to 1 per 1000000 travelers) for travelers to Africa and Oceania, and during the past decade it has increased more than fivefold for travelers to Kenya. The risk is intermediate (1 per 5000000 to 1 per 12000000) for travelers to Haiti and the Indian subcontinent, and low (less than 1 per 50000000) for travelers to Asia and Central and South America.

Risk factors for malaria include the itinerary, length of travel, and the use and efficacy of preventive measures. Traveler surveys indicate that chemoprophylaxis is used by more than 80% of United States travelers to Africa, but by only one-third of travelers to Haiti, and less than 10% of travelers to rural areas of Southeast Asia. Prophylaxis-specific attack rates in travelers in 1986 suggest that chloroquine prophylaxis was oflimited efficacy in suppressing P.falciparum infections in travelers to East Africa, but was highly effective for travelers to Nigeria. Travelers to East and Central Africa are advised to carry a presumptive treatment dose of Fansidar, but only one-third of travelers comply with this recommendation. In recent years use of antimosquito measures has been emphasized; 55% of travelers to Africa use these. Malaria risk can bereduced by modifying the behavior of travelers. Detailed information is essential for targeting and evaluating prevention efforts.