ABSTRACT
West Nile virus [WNV] is a vector-borne agent that is maintained within a bird-mosquito cycle. In humans and equids, infection by this agent is usually asymptomatic, or characterized by a mild febrile illness. However, fatal meningoencephalitis or encephalitis may occur. The aim of this study was to evaluate the prevalence of WNV infection and correlation of this organism with host and environmental determinants in horses in Khuzestan province. In 2011-2012, serum samples of 155 horses were randomly collected from 7 zones of Khuzestan province and were examined by ELISA assay. Seroprevalence of WNV infection was 70.3% [95% CI: 63.1-77.5%]. Statistical analysis showed that age, zone, presence of lake, type of bed, time of sampling, staying out of the stable after sunset and the method of insect control are significantly associated with infection [p<0.05] but sex, presence of river, wall condition, presence of rubbish dump and history of disease are not significantly associated with infection [p>0.05]. The results of the present study confirm that the WNV infection exists in Khuzestan province. Considering the local weather conditions and the facility of vector-borne transmission, the health authorities should take measures to prevent and control the infection