Increased gametocytemia after treatment: An early parasitological indicator of emerging sulfadoxine-pyrimethamine resistance in falciparum malaria

Abstract

Background. Although malaria treatment aims primarily to eliminate the asexual blood stages that cause illness, reducing the carriage of gametocytes is critical for limiting malaria transmission and the spread of resistance. Methods. Clinical and parasitological responses to the fixed-dose combination of sulfadoxine and pyrimethamine in patients with uncomplicated falciparum malaria were assessed biannually since implementation of this treatment policy in 1998 in Mpumalanga Province, South Africa. Results. Despite sustained cure rates of > 90% (P = .14), the duration of gametocyte carriage increased from 3 to 22 weeks (per 1000 person-weeks) between 1998 and 2002 (P