Investigation of West Nile Fever Seroprevalence and Associated Risk Factors among Horses in Egypt

Determination of the seroprevalence and risk factors associated with West Nile Fever (WNF) in horses is essential for adoption of effective prevention strategies. Our objective was therefore to determine the seroprevalence and identify the risk factors associated with West Nile virus (WNV) infection in the most densely horse populated provinces in Egypt. A cross-sectional study was conducted on 930 horses distributed over five provinces in the Nile Delta of Egypt in 2018. The randomly selected horses from geographical studied areas were serologically tested for WNF, and the horses’ information was obtained from owners. Four variables (geographic location, breed, gender, and age) were used for risk analysis. A total of 156 (16.8%) serum samples were serologically positive for WNV. The highest prevalence of WNV infection was between mixed breed (21.5%), male (26.4%) horses with age ≥ 15 years (68.1%). Age showed the highest risk for the infection with WNV (OR = 4.3, 95% CI 3.0 to 6.2). Gender and breed also showed important risk factors for WNF infection in horses (OR = 2.4, 95% CI 1.6 to 3.7; OR = 1.9, 95% CI 1.2 to 2.8, respectively). However, geographic location seems to have no impact on the seroprevalence of WNV infection among horses in the Nile Delta of Egypt. Our findings strongly recommend intensive surveillance and implementation of effective control and prevention strategies against WNF especially in male of mixed breed horses with ages ≥ 15 years.