Primaquine as prophylaxis for malaria for nonimmune travelers: A comparison with mefloquine and doxycycline.

Malaria prophylaxis for travelers is a controversial issue. The commonly used regimens are associated with side effects, low compliance, or low efficacy, which have raised concern regarding their use. In addition, they are inefficient against the tissue stage of the parasite and thus do not prevent relapses of Plasmodium vivax infection. Primaquine is aimed at the pre-erythrocytic stage and thus may be a potential causal-prophylactic treatment that can abolish the need for long postexposure therapy. During 1995-1998, we followed retrospectively travelers who joined rafting trips to an area in Ethiopia where both P. vivax and Plasmodium falciparum are hyperendemic. Of the 106 travelers who received primaquine, 5.7% developed malaria; of the 19 doxycycline recipients, 53% developed malaria; and of the 25 mefloquine recipients, 52% developed P. vivax malaria (>/=3 months after return from the area of endemicity). Primaquine was well tolerated, and only 1 withdrawal from therapy (due to gastrointestinal symptoms) was reported. Primaquine was shown to be a safe and effective prophylactic drug against both P. falciparum malaria and P. vivax malaria in travelers.