Plasmodium vivax Malaria Relapses after Primaquine Prophylaxis

Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 12, No. 11, November 2006 1795 contacts with clandestine gold panners, mainly Brazilian illegal residents. This population, in which malaria incidence is almost impossible to evaluate, comes from Amapa State, where the incidence of malaria is increasing (5). In 2003, 60.9% of patients with malaria cases at Cayenne Hospital had a Brazilian name compared with 35.4% in 2000 (6). Also, the gold panners diverted the river and built basins where vectors could easily multiply (7). Initial malaria attacks were treated with chloroquine or quinine. Five patients experienced >1 relapses (maximum 3 relapses). The relapses were treated with 50-mg daily doses of primaquine for 4 patients and by chloroquine for the fifth patient. Two patients had relapses after receiving primaquine. Primaquine resistance information was not available. However, resistance to primaquine has emerged in P. vivax strains (8). We recommended that pre-impregnated battlefield uniforms be available for French policemen and chemoprophylaxis adherence be reinforced by directly observed intake by supervisory staff. Relapses of P. vivax malaria are a major therapeutic problem, particularly after primaquine therapy.