Association between domesticated animal ownership and Plasmodium falciparum parasite prevalence in the Democratic Republic of the Congo: a national cross-sectional study

Abstract

Domesticated animal ownership is an understudied aspect of the human environment that influences mosquito biting behaviour and malaria transmission, and is a key part of national economies and livelihoods in malaria-endemic regions. In this study, we aimed to understand differences in Plasmodium falciparum prevalence by ownership status of common domesticated animals in DR Congo, where 12% of the world's malaria cases occur and anthropophilic Anopheles gambiae vectors predominate. In this cross-sectional study, we used survey data from individuals aged 15-59 years in the most recent (2013-14) DR Congo Demographic and Health Survey and previously performed Plasmodium quantitative real-time PCR (qPCR) to estimate P falciparum prevalence differences by household ownership of cattle; chickens; donkeys, horses, or mules; ducks; goats; sheep; and pigs. We used directed acyclic graphs to consider confounding by age, gender, wealth, modern housing, treated bednet use, agricultural land ownership, province, and rural location. Of 17 701 participants who had qPCR results and covariate data, 8917 (50·4%) of whom owned a domesticated animal, we observed large differences in malaria prevalence across types of animals owned in both crude and adjusted models. Household chicken ownership was associated with 3·9 (95% CI 0·6 to 7·1) more P falciparum infections per 100 people, whereas cattle ownership was associated with 9·6 (-15·8 to -3·5) fewer P falciparum infections per 100 people, even after accounting for bednet use, wealth, and housing structure. Our finding of a protective association conferred by cattle ownership suggests that zooprophylaxis interventions might have a role in DR Congo, possibly by drawing An gambiae feeding away from humans. Studies of animal husbandry practices and associated mosquito behaviours could reveal opportunities for new malaria interventions. The National Institutes of Health and the Bill & Melinda Gates Foundation. For the French and Lingala translations of the abstract see Supplementary Materials section.