Abstract
Bovine viral diarrhea virus (BVDV) is a globally significant pathogen causing reproductive losses, immunosuppression, and reduced productivity in cattle. In East Africa, smallholder farming systems dominate, yet comprehensive data on BVDV seroprevalence and associated risk factors remain scarce. This cross-sectional study aimed to determine the seroprevalence of BVDV and identify herd-level and animal-level risk factors in smallholder dairy farms across selected regions of Kenya, Ethiopia, and Tanzania. A total of 1,200 cattle from 240 farms were sampled between March and November 2023. Serum samples were tested for BVDV-specific antibodies using a commercial indirect ELISA. A structured questionnaire was administered to collect data on farm management, biosecurity practices, animal health, and demographic characteristics. Multivariable logistic regression models were employed to assess associations. Overall animal-level seroprevalence was 42.5% (95% CI: 39.7–45.3), while herd-level seroprevalence was 68.3% (95% CI: 62.1–74.0). Significant risk factors included introduction of new animals without quarantine (OR = 3.2, p 20 animals (OR = 1.9, p = 0.02) and contact with neighboring herds (OR = 2.2, p = 0.01) were also associated. These findings highlight a high BVDV burden in East African smallholder systems and underscore the need for targeted interventions, including biosecurity improvements, vaccination strategies, and awareness programs to mitigate economic losses.