Seroprevalence of Rift Valley fever virus and factors associated with exposure in south-central Uganda.

BACKGROUND

Rift Valley fever (RVF) poses a recurring public health and economic challenge in Uganda's cattle corridor. It is a mosquito-borne zoonotic disease caused by the Rift Valley fever virus (RVFV), with high livestock density, favorable rainfall patterns, and close human-animal interaction facilitating viral transmission and disease outbreaks. Although RVF outbreaks have occurred, data on human exposure in south-central Uganda remain limited.

METHODS

This cross-sectional study assessed the seroprevalence and associated factors of RVFV exposure among selected communities in the greater Masaka-Rakai region of south-central Uganda. Archived human sera (n = 1,199) retrospectively collected between June 2018 and October 2020 from the population-based Rakai Community Cohort Study were analyzed using both indirect in-house and commercial ID Screen® RVF competition enzyme-linked immunosorbent assays (ELISAs) to detect RVFV IgG antibodies. Household census and socio-demographic data were linked to serological results, and logistic regression was performed to identify factors associated with seropositivity.

RESULTS

RVFV IgG antibodies were detected in 86 of 1,199 (7.8%) individuals. In multivariable analysis, RVFV seropositivity was significantly associated with residence in agrarian communities and older age groups (25-34 and ≥ 35 years), while pig ownership was associated with lower risks of exposure.

CONCLUSION

These findings suggest RVFV human exposure in south-central Uganda and emphasize the need for strengthened surveillance, targeted prevention, and One Health interventions to protect high-risk groups.