Longitudinal malaria studies in rural Northeast Thailand. Chloroquine treatment of falciparum malaria infections.

The efficacy of chloroquine in the treatment of falciparum malaria was studied in two villages in Northeast Thailand, an area endemic for chloroquine-resistant falciparum infections. Chloroquine did not appear to reduce the duration or density of parasitemias experienced by asymptomatic villagers, but did benefit, usually temporarily, many subjects with symptomatic or high-density infections. These observations suggest that the high prevalence of chloroquine-resistant infections in the villages is similar to data from the hospital and clinics serving the area. The question whether chloroquine should remain available to this population should be evaluated.