Molecular and serological survey of Akabane virus infection in sheep in the Mediterranean Region of Turkey

This study was carried out to explore serological and molecular features of Akabane virus (AKAV) in sheep flocks with abortion problems and determine the potential role of Culicoides spp. in the transmission of AKAV. For this purpose, EDTA whole blood (n = 301), sera (n = 301) and aborted foetuses samples (n = 87) were obtained from epidemiologically independent flocks (n = 87) in the Mediterranean region of Turkey during the months of October 2015 and January 2016. Culicoides spp. were trapped from October to November 2015. A commercial competitive ELISA kit was used for the detection of AKAV anti-G1 antibodies in the sera samples. Real-time reverse-transcriptase PCR was used to detect viral RNA in EDTA whole blood, aborted foetuses and Culicoides samples. Genetic characterization of the local AKAV field isolates was conducted by sequencing the S segment of AKAV. Antibodies against AKAV were detected in 135 (44.9%) of 301 animals. Among the 87 flocks, 68 (78.2%) had one or more seropositive animals. Viral RNA was detected in 11 of the 87 aborted foetuses. Furthermore, real-time RT-PCR detected positive viral RNA in Culicoides midges. AKAV RNA was not detected in EDTA whole blood samples. Phylogenetic analysis showed that the field isolates of AKAV obtained in this study clustered within genogroup Ib. The sequence analysis of the mitochondrial cytochrome oxidase subunit I gene of Culicoides spp. showed that the species of Culicoides in AKAV-positive pools was Culicoides imicola. The results of this study showed that AKAV infection plays a role in abortion cases of sheep in the Mediterranean region of Turkey. Therefore, a control program is needed against to AKAV infection.