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

Akabane virus infection in Eastern Mediterranean Region in Turkey: Culicoides (Diptera: Ceratopogonidae) as a possible vector

Akabane virus (AKAV), which causes Akabane disease, is an arthropod-borne virus (arbovirus) transmitted by Culicoides biting midges and mosquitoes. AKAV is an important pathogen that causes abortion and congenital anomalies in ruminants. In this study, we determined the prevalence of AKAV infection and identified possible viral vectors in Turkey's Eastern Mediterranean region. The presence and prevalence of AKAV infection were assessed using serological and virological methods. Serologically, the prevalence of AKAV antibodies in cattle, sheep and goats were 44.74% (400/894), 22.90% (60/262) and 14.52% (63/434), respectively, while the total prevalence was 32.89% (523/1590). AKAV-specific nucleic acid amplicons were obtained by real-time RT-PCR from 1.13% (9/799) and 1.74% (5/288) of the cattle and sheep tested, respectively. No goats were positive for AKAV RNA. Overall, AKAV-specific nucleic acid amplicons were detected in 0.87% (14/1604) of the sampled ruminants. In addition, specimens of the assumed vector, Culicoides, were caught using light traps and identified. Ten Culicoides species were detected in the area, of which Culicoides schultzei complex was the dominant species although 32 specimens could not be identified at the species level. These were defined as Culicoides spp. AKAV nucleic acid was detected in C. schultzei, Culicoides longipennis and Culicoides circumscriptus. Phylogenetic analysis indicated two different AKAV genogroups (genogroups Ib and genogroups II) while potential AKAV vectors in this region are C. schultzei complex, C. longipennis and C. circumscriptus.

Genomic characterization of pestiviruses isolated from bovine, ovine and caprine foetuses in Turkey: A potentially new genotype of Pestivirus I species

This study was carried out to investigate the frequency and genetic diversity of pestiviruses in abortion cases in cattle and small ruminants in Turkey. During January 2012 and December 2017, a total of 2029 aborted foetuses (553 bovine foetuses, 1,388 sheep foetuses and 88 goat foetuses) were collected from different regions of Turkey. Real-time RT-PCR (RRT-PCR) assays were used to detect pestiviral RNA in aborted foetuses. To confirm the cause of abortion, pestivirus-positive foetuses were also examined for the presence of Brucella spp., Campylobacter spp., Chlamydophila abortus (C. abortus), akabane virus, bluetongue virus and Schmallenberg virus by molecular detection methods. Pestiviral RNA was detected in 61 (11%) of the 553 bovine foetuses, 124 (8.9%) of the 1,388 sheep foetuses and 3 (3.4%) of the 88 goat foetuses. Furthermore, C. abortus DNA was detected in 3 pestivirus-positive sheep foetuses, whereas other infectious agents were not detected in pestivirus-positive foetuses. Genetic characterization of the pestivirus RRT-PCR positive samples was conducted by sequencing 5' untranslated (5' UTR) and non-structural autoprotease (N^pro ) genomic regions. A total of 68 sequences were obtained, and phylogenetic analyses revealed that all sequences belonged to BVDV-1, including 1b (8/68), 1f (2/68), 1l (4/68), 1r (10/68), Aydin-like pestivirus (20/68) and one unknown genotype (24/68). The 5' UTR and N^pro sequences of this unknown genotype differed from pestiviruses previously described, providing evidence for the presence of an emerging genotype within the species Pestivirus I, tentatively named as 'Konya-like' pestivirus. 'Konya-like' pestivirus was the dominant genotype in sheep foetuses, whereas Aydin-like pestivirus was found to be the predominant genotype in bovine foetuses. To the best my knowledge, this is the first report of Aydin-like pestivirus infection in cattle. The information provided in this study contributes to the understanding the dissemination and evolution of pestiviruses and could be beneficial for developing more effective vaccines.