Serological evidence of high West Nile virus exposure in equines of Oman and analysis of associated risk factors

West Nile virus (WNV) is a mosquito-borne pathogen capable of causing encephalitis in humans and horses. Horses share mosquito vectors with humans and seroconvert following infection, making them valuable sentinel species for WNV surveillance. In this cross-sectional study, 453 equines from 52 locations across eight governorates of northern Oman were screened for anti-WNV IgG antibodies using a competitive ELISA, with IgG-positive samples further tested for IgM to detect recent infection. Overall apparent seroprevalence was 47.0% (95% CI 42.3–51.8%; 213/453). No IgM-positive samples were detected, indicating past rather than recent exposure. Multivariable logistic regression identified age and proximity to surface water as independent risk factors for seropositivity: odds increased with age (5.1–10 years: OR 2.47, 95% CI 1.59–3.85; >10 years: OR 4.40, 95% CI 2.56–7.55) and with closer proximity to water bodies (≤ 200 m: OR 2.24, 95% CI 1.27–3.98; 201–500 m: OR 2.43, 95% CI 1.21–4.88). No significant associations were found with breed, sex, or interspecies contact. These findings indicate substantial WNV exposure among equines in northern Oman and support their role as sentinel hosts at the animal-human interface, underscoring the need for integrated One Health surveillance of WNV and related orthoflaviviruses.