Recrudescence and relapse in vivax malaria.

01 Jan 1948
COATNEY GR, COOPER WC

Plasmodium vivax resistance to chloroquine (CQ) has been reported worldwide, although the World Health Organization clinical drug efficacy studies protocol does not permit classification of patient outcomes. We enrolled 40 patients with P. vivax malaria in northeastern Cambodia, where >17% treatment failures were previously reported. Patients were treated with CQ (30 mg/kg) and followed for 2 months, with frequent clinical examination and capillary blood sample collection for microscopy, molecular parasite detection and genotyping, and drug concentration measurements. Reinfections were prevented by relocating patients to a transmission-free area. No evidence of CQ resistance was observed. Our data suggest that P. vivax antimalarial drug resistance is likely overestimated and that the current guidelines for clinical drug studies of P. vivax malaria need to be revised.