Clearance of falciparum parasitaemia with a single dose sulfadoxine-pyrimethamine in Vientiane, Laos.

A total of 49 semi-immune Laotians aged 3 to 49 years, with falciparum malaria were treated with a single dose of sulfadoxine pyrimethamine (1500 mg, 75 mg, adult dose), in Vientiane, Laos. On day 7 after treatment the 49 cases were asymptomatic with complete disappearance of patent asexual parasitaemia. The result is compared with that obtained from treating 48 similar cases with a standard dose of chloroquine over 3 days.