Plasmodium falciparum gametocyte kinetics and infectivity may differ between chronic and incident infections. Children aged 5-10 years were recruited from an area of high malaria transmission in Burkina Faso into two cohorts: an incident cohort in which new infections were followed after parasite clearance (n=48), and a chronic cohort in which asymptomatic infections were identified and followed (n=60). Parasite kinetics were assessed daily with repeated mosquito feeding assays to quantify transmission potential. All participants were treated upon detection of symptoms; 92% (44/48) of the incident cohort developed symptoms within 35 days, compared to 23% (14/60) of the chronic cohort. All individuals with chronic infection became gametocytaemic during follow-up, whereas only 35% (17/48) in the incident cohort produced gametocytes before becoming symptomatic. Parasite multiplication rate (PMR) and the relative abundance of ap2-g and gexp-5 transcripts were positively associated with gametocyte production. Antibody responses were higher and PMR lower in chronic infections. The presence of symptoms and sexual stage immune responses were associated with reductions in gametocyte infectivity to mosquitoes. We observed that most incident infections required treatment before the density of mature gametocytes was sufficient to infect mosquitoes. In contrast, chronic, asymptomatic infections represented a significant source of mosquito infections. Our observations support the notion that malaria transmission reduction may be expedited by enhanced case management, involving both symptom-screening and infection detection.

Plasmodium falciparum gametocyte kinetic