Seroepidemiological survey of bovine leukemia virus infection in cows in Khuzestan province

Bovine leukemia virus (BLV) is a member of the Delta retro virus genus (family Retroviridae) and can cause persistent lymphocytosis and lymphosarcoma in cattle that is described as enzootic bovine leucosis (EBL). This disease causes significant economic losses associated with the costs of control and eradication programs. Control programs of leucosis are based on the screening of cows by serological methods and removing the infected cows. The aim of this study was to evaluate the seroprevalence of bovine leukemia virus in cattle in Khuzestan province. Serum samples from 527 cattle were randomly collected in Ahvaz, Baghmalek, Shooshtar, Gotvand, Shadegan, Hendijan, Behbahan, Ramhormoz and Susangerd cities and were examined by ELISA assay. Seroperevalence rate of bovine leukemia virus was 6.64% (95% CI: 4.51-8.77). Statistical analysis indicated no significant association between infection and age or breed. Relative frequency of infection was higher in female cows than males, but this difference was not significant and odds of infection in female cows than males were 2.6 (95% CI: 0.35-19.59). Prevalence rate of infection between industrial (15%) and nonindustrial (3.4%) husbandry was significantly different (p<0.001) and odds of infection in industrial husbandry than nonindustrial was 4.97 (95% CI: 2.43-10.16). Prevalence rate in Shadegan, Baghmalek, Behbahan, and Susangerd were 23.5%, 20.3%, 7.2% and 1.7%, respectively, but infection was not observed in Ahvaz, Shooshtar, Gotvand, Ramhormoz and Hendijan (p<0.001) and 30.8% of fluctuation of disease was justified by geographical location. This study confirms that bovine leukemia virus exists in Khuzestan province. Prevention and control measures should be considered by health authorities.