An Outbreak of Malaria in US Army Rangers Returning From Afghanistan

CONTEXT With numerous US military personnel currently deployed throughout the world, military and civilian health care professionals may encounter imported malaria from this population. OBJECTIVE To identify malaria in US Army personnel deployed to a combat zone. DESIGN, SETTING, AND PATIENTS Case series in the US Army health care system. A total of 38 cases of malaria were identified in a 725-man Ranger Task Force that deployed to eastern Afghanistan between June and September 2002. MAIN OUTCOME MEASURES Identification of malaria cases and soldiers’ self-report of compliance with antimalarial measures. RESULTS A total of 38 patients were infected with Plasmodium vivax, yielding an attack rate of 52.4 cases per 1000 soldiers. Diagnosis was confirmed a median of 233 days (range, 1-339 days) after return from the malaria endemic region, with additional laboratory findings noting anemia and thrombocytopenia. One case was complicated with acute respiratory distress syndrome during the patient’s primary attack and a spontaneous pneumothorax during relapse. This case accounted for 1 of 2 relapse cases in the study population. From an anonymous postdeployment survey of 72% (521/725) of the task force, the self-reported compliance rate was 52% for weekly chemoprophylaxis, 41% for terminal (postdeployment) chemoprophylaxis, 31% for both weekly and terminal chemoprophylaxis, 82% for treating uniforms with permethrin, and 29% for application of insect repellent. CONCLUSIONS Delayed clinical presentation can occur with P vivax. Symptoms are often vague, but malaria should be included in the differential diagnosis for soldiers returning from an endemic region. Suboptimal compliance with preventive measures can result in a malaria outbreak.