Evaluation of reported malaria chemoprophylactic failure among travelers in a US university exchange program, 2002

Background. Travelers to malarious areas are at risk of acquiring malaria; however, with chemoprophylaxis and prompt, effective therapy, serious complications of infection are generally preventable. In June 2002, we investigated a report of a cluster of malaria cases among US university staff and students who visited Ghana and were reportedly adherent to appropriate malaria chemoprophylaxis. Methods. We administered a questionnaire to all participants and collected blood specimens for malaria serological examinations from those reporting malaria infection diagnosed by blood smear in Ghana. Results. Of the 33 participants, 25 completed the questionnaire. Twenty-four took a Centers for Disease Control and Prevention - recommended chemoprophylactic drug; 14 ( 56%) of 25 reported complete adherence to therapy. Twenty (80%) of 25 subjects reported symptoms consistent with possible malaria. Six of these persons reported a microscopic diagnosis of malaria and were treated in Ghana. Serological examination for malaria was performed using blood samples obtained from 5 of these participants; the results for all were negative, suggesting that incorrect diagnoses of malaria were made. Conclusions. Misdiagnosis of malaria made while a person is abroad may not only lead to erroneous reports of drug resistance, but it could also result in unnecessary administration of antimalarial treatment. Health care providers and public health authorities must critically evaluate reports of chemoprophylactic failures and disseminate accurate information to travelers.