New Culicoides Vector Species for BTV Transmission in Central and Central West of Anatolia

Abstract

The aim of this study was to investigate the presence of BTV infection and possible vector species in different regions of Turkey. In the study, blood samples taken from 666 Akkaraman sheep were examined. 2000 Culicoides specimens were captured by light traps from the same provinces and 20 Culicoides spp. were identified. Blood sera samples were investigated by c-ELISA and SNT for detecting Abs to BTV. Sera samples were detected as positive 67 (10.06%) and 160 (24.02%) by SNT and ELISA, respectively. SN50 values of the 67 positive sera samples by SNT were detected between 1/2.38 and 1/200. All sheep blood samples and pools became Culicoides spp. samples were examined for BTV Ag presence by BTACE. Thirty six (5.40%) blood samples were detected as positive, but no from Culicoides pools. In the meantime, all sheep blood samples and Culicoides samples were directly investigated for BTV genome by one step RT-PCR. Fourteen (2.10%) blood samples and 7 (11.11%) Culicoides species were detected as positive. Also, the blood samples and the Culicoides samples were inoculated into Vero cell culture and passaged 5 times. Twenty nine (4.35%) blood samples cultured in Vero cell culture lines showed CPE but non CPE was observed in Culicoides samples. While 5 (17.24%) of 29 CPE positive isolates were identified as BTV by One Step RT-PCR. Total 26 samples (14 blood samples, 7 Culicoides samples and 5 supernatants) which detected BTV genome positive by One Step RT-PCR were serotyped. At the end of the study, while 23 of 26 samples were serotyped as BTV-9, two samples were serotyped as BTV-4. One sample (C. punctatus) from Culicoides was not serotyped as none of serotypes of BTV. In the present study, BTV was isolated for the first time from C. circumscriptus, C. kibunensis, and C. punctatus in Turkey.