A Cross-Sectional Study of Rift Valley Fever Exposure in Humans and Livestock in Southwestern Uganda Using a One...

Rift Valley fever (RVF) transmission has intensified in southwestern Uganda since 2016. To quantify human and livestock exposure and associated risks, we conducted a cross-sectional serosurvey in Isingiro, Kabale and Rubanda districts between October and November 2023. A total of 766 humans and 2383 livestock were sampled and tested for RVF antibodies using ELISA, with structured questionnaires capturing demographic, behavioral and environmental data. Human seroprevalence was 11.5% (88/766), varying by district (13.8% Isingiro, 11.8% Rubanda, 6.8% Kabale; p = 0.04). Independent predictors from the multivariate model included raw-meat consumption (aOR 6.11; 95% CI 1.16-27.80), cattle ownership (aOR 2.33; 95% CI 1.27-4.36), male sex (aOR 1.64; 95% CI 1.02-2.66) and younger age compared with ≥50 years (31-49 years: aOR 2.02; 95% CI 1.20-3.48; 18-30 years: aOR 2.37; 95% CI 1.04-5.14). Herd-level seroprevalence was 42.5% (204/480), associated with cattle presence (aOR 6.48; 95% CI 4.10-10.40), lack of carcass burial (aOR 15.70; 95% CI 4.23-63.60), on-farm slaughter (aOR 2.14; 95% CI 1.21-3.89) and increased mosquito activity (aOR 1.75; 95% CI 1.13-2.73). Animal-level seroprevalence was 14.6% (347/2383), highest in cattle (33.8%), with cattle having markedly higher odds than goats (aOR 6.73; 95% CI 4.96-9.14). These findings demonstrate substantial transmission and highlight cattle-centered interfaces as primary targets for control to humans.