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.

Participants were permanent residents in the  Sapone Marche and Pissy LHF catchment areas and were enrolled in a total of 181 households. Households were randomized into 3 study arms that received different levels of care.

Standard of care with Passive case detection (PCD) (performed in arms 1, 2 & 3): All participants received unique identification cards for use when attending two designated local health facilities. Clinical malaria episodes were passively monitored, with axillary temperature and medical history recorded, and malaria diagnosed by conventional Rapid Diagnostic Test (RDT; First Response Malaria Ag. pLDH/HRP2, specific for P. falciparum and/or other Plasmodium species). 

Weekly fever screening, testing, and treatment (arms 2 & 3): All participants in arms 2 and 3 were visited weekly by a community health worker to screen for fever. Participants with a current fever (≥ 37.5°C) or a history of fever in the last 24 hours were referred to a health facility and an RDT was performed.

Monthly Mass Testing and Treatment (MTAT; arm 3): In arm 3, one weekly fever screening visit per month was replaced by MTAT,  where participants presented at a central meeting point for testing by conventional RDT. RDT-positive participants were referred to a health facility for treatment.

At the start and end of each transmission season, a cross-sectional survey was conducted on all study participants (4 surveys in total). Finger-prick blood samples were taken for molecular assessment of parasite and gametocyte prevalence and density, and axillary temperature was measured. Participants with a current fever (≥37·5°C) or a history of fever in the last 24 hours were referred to an LHF for malaria diagnosis by RDT and treatment.