WHOLE-BLOOD CHLOROQUINE CONCENTRATIONS WITH PLASMODIUM-VIVAX INFECTION IN IRIAN-JAYA, INDONESIA

Whole blood concentrations of self-administered chloroquine (CQ) and i ts metabolite desethylchloroquine (DCQ) were measured in 168 patients with microscopically confirmed infection by Plasmodium vivax in northe astern Irian Jaya, Indonesia. The study consisted of both survey and p assive case detection in four separate villages between 1992 and 1994. The subjects were Javanese people 4-51 years old who had lived in the Arso region for up to two years. The sum of CQ and DCQ ranged from 0 to 8,342 ng/ml of whole blood, and 122 subjects (73%) had greater than or equal to 100 ng/ml of CQ plus DCQ, the estimated minimally effecti ve concentration (MEG) in whole blood against chloroquine-sensitive P. vivax. Among 56 subjects reporting to a clinic with symptoms of malar ia, 53 (95%) had ordinarily effective levels of chloroquine in blood. Among 109 largely asymptomatic malaria patients found by survey case d etection, 69 (63%) had chloroquine blood levels greater than the MEG. Virtually all clinical and most subclinical vivax malaria in this regi on occurs despite ordinarily effective levels of chloroquine in blood.