Seroepidemiological survey of bluetongue disease in sheep in Khuzestan province

Bluetongue is an infectious and non-contagious disease of domestic and wild ruminants, caused by bluetongue virus. This virus is a member of the genus Orbivirus and family Reoviridae. Clinical signs are usually detected in fine wool breeds of sheep and include fever, facial oedema, hyperemia and ulceration of oral mucosa, coronitis, lameness, abortion and death. The aim of this study was to evaluate the prevalence of bluetongue infection and association of this organism with host and environmental determinants in sheep in Khuzestan province. Serum samples from 556 sheep were randomly collected in Ahvaz, Hendijan, Baghmalek, Shadegan and Dezfool cities and were examined by ELISA assay. Seroperevalence rate of bluetongue was 55.9 % (95% CI: 51.8-60%). Logistic regression showed that the odds of infection was increased with increase of age (OR: 1.17 and 95% CI: 1.06-1.29). Relative frequency of infection was higher in male sheep than female sheep (P>0.05) and odds of infection in male sheep than females was 1.29 (95% CI: 0.71-2.37). Prevalence rate were in sheep with and without history of abortion 47.8% and 55.7% respectively (P>0.05) and odds of infection in sheep with history of abortion than healthy sheep was 0.63 (95%CI: 0.27-1.46). Prevalence rate in Ahvaz, Hendijan, Baghmalek, Shadegan and Dezfool were 50.2%, 12.5%, 60.5%, 82.8% and 85.7% respectively(P<0.001) and 33.5% of fluctuation of disease was justified by geographical location. This study confirms that bluetongue virus exists in Khuzestan province. According to local weather conditions and facility of vector-borne diseases, prevention and control measures should be considered by health authorities.