LONG-TERM EFFICACY OF PRIMAQUINE IN THE TREATMENT OF VIVAX MALARIA INNONIMMUNE TRAVELERS

Fifty-six travelers presenting with vivax malaria to a German travel c linic were followed regularly for at least 18 months between 1984 and 1992 to investigate the long-term efficacy of primaquine in nonimmune patients without reinfection. All received a standard treatment of 15 mg of primaquine a day for 14 days following an initial total dose of 1,500 mg of chloroquine (base) given over a 48-hr period. None of the patients visited countries endemic for malaria during the period of ob servation. In seven patients (12.5%), relapses were confirmed microsco pically by detection of malaria parasites in blood films. The frequenc y of relapses varied between one and four per patient and these occurr ed between 60 and 252 days after treatment. Four of these seven patien ts had acquired infection in Papua New Guinea or eastern Indonesia, wh ile only five (10.2%) of the remaining 49 patients without relapses ha d traveled to these areas prior to referral (P < 0.01).