Seroepidemiology of Bluetongue Virus Infection in Northeast and Southeast Anatolia, Turkey

Abstract

Bluetongue virus infection is an arboviral disease, which infects domestic and wild ruminants. It is characterized by oedema and hemorrhages, especially in reproductive system of both female and male animals. It causes economic losses associated with decrease in fertility problems, abortions and congenital malformation. Bluetongue virus a member of orbivirus genus within the family Reoviridae has 24 serotypes. There is no cross-neutralization between 24 serotypes and that is the biggest problem for prevention and control. For the success of the prophylactic immunization, serotype-spesific vaccine should be used. This research's first step is to determine the seroprevalance in northeast and southeast Anatolian regions in Turkey by selecting two local governmental herds per region. After selection regional herd candidates, one "sentinel herd" in each region was established by selecting seronegative individuals. These herds sampled every month during one year and monitored for bluetongue specific antibody using competitive ELISA. Seroconverted individuals' blood samples tested by antigen capture ELISA and the process of the virus isolation were started. There was no seroconversion in the sentinel herd selected from northeast Anatolia while the seroconversion was detected in the sentinel herd from southeastern Anatolia in Turkey. Blood samples of seroconverted cattle were tested by antigen-capture ELISA in order to detect possible bluetongue viruses. Viral antigen was not detectable at the end of antigen-capture ELISA. Serum samples of seroconverted animals in different periods were re-tested using virus neutralizing assay for detection of individual SN50 values. It was found that BTV type 9 was circulating in the herd from southeastern Anatolia during the sampling period.