The effect of community-driven larval source management and house improvement on malaria transmission when added to the standard malaria control strategies in Malawi: a cluster-randomized controlled trial

22.05.21
Robert S. McCann, Alinune N. Kabaghe, Paula Moraga, Steven Gowelo, Monicah M. Mburu, Tinashe Tizifa, Michael G. Chipeta, William Nkhono, Aurelio Di Pasquale, Nicolas Maire, Lucinda Manda‑Taylor, Themba Mzilahowa, Henk van den Berg, Peter J. Diggle, Dianne J. Terlouw, Willem Takken, Michèle van Vugt and Kamija S. Phiri

Abstract

Background: Current standard interventions are not universally sufcient for malaria elimination. The efects of community-based house improvement (HI) and larval source management (LSM) as supplementary interventions to the Malawi National Malaria Control Programme (NMCP) interventions were assessed in the context of an intensive community engagement programme.

Methods: The study was a two-by-two factorial, cluster-randomized controlled trial in Malawi. Village clusters were randomly assigned to four arms: a control arm; HI; LSM; and HI+LSM. Malawi NMCP interventions and community engagement were used in all arms. Household-level, cross-sectional surveys were conducted on a rolling, 2-monthly basis to measure parasitological and entomological outcomes over 3 years, beginning with one baseline year. The primary outcome was the entomological inoculation rate (EIR). Secondary outcomes included mosquito density, Plasmodium falciparum prevalence, and haemoglobin levels. All outcomes were assessed based on intention to treat, and comparisons between trial arms were conducted at both cluster and household level.

Results: Eighteen clusters derived from 53 villages with 4558 households and 20,013 people were randomly assigned to the four trial arms. The mean nightly EIR fell from 0.010 infectious bites per person (95% CI 0.006–0.015) in the baseline year to 0.001 (0.000, 0.003) in the last year of the trial. Over the full trial period, the EIR did not difer between the four trial arms (p=0.33). Similar results were observed for the other outcomes: mosquito density and P. falciparum prevalence decreased over 3 years of sampling, while haemoglobin levels increased; and there were mini‑ mal diferences between the trial arms during the trial period.