The impact of weekly fever-screening and treatment and monthly RDT testing and treatment on the infectious reservoir of malaria in Burkina Faso: results from a cluster-randomised trial

The majority of malaria infections in endemic countries are asymptomatic and a source of onward transmission to mosquitoes. Malaria transmission and disease burden could be reduced by improving early detection and treatment of these infections with active screening approaches. In an 18-month cluster-randomized study in Sapone, Burkina Faso, households were enrolled and randomised to 1 of 3 arms: arm 1 - control; arm 2 - active weekly screening for febrile individuals and treatment if rapid diagnostic test (RDT) positive; or arm 3 – active weekly fever-screening (as arm 2) plus monthly RDT-testing regardless of symptoms. The primary outcome was parasite prevalence by qPCR in the end-of-study cross-sectional survey. Secondary outcomes included parasite and gametocyte prevalence and density in all three end-of-season cross-sectional surveys, incidence of infection, and the transmissibility of infections to mosquitoes. A total of 906 individuals were enrolled during 2 phases. In Phase 1, 412 individuals were enrolled between August 9 and 17, 2018, and in Phase 2, 494 individuals were enrolled between January 10 and 31, 2019. In the end-of-study cross-sectional survey, malaria parasite prevalence by qPCR was statistically significantly lower in arm 3 (29·26% 79/270), but not in arm 2 (45·66% 121/265), when compared to arm 1 (48·72% 133/273) (RR = 0·65, 95%CI = 0·52 to 0·81, P=0·0001). Total parasite and gametocyte prevalence and density were also significantly lower in arm 3 in all surveys. The largest differences were seen at the end of the dry season, with gametocyte prevalence 78·38 % and transmission potential 98·20% lower in arm 3 vs arm 1. Active monthly RDT testing and treatment can reduce parasite carriage and the infectious reservoir of malaria to <2% when used during the dry season. This insight may inform approaches for malaria control and elimination.

Keywords