Molecular evidence of schmallenberg virus associated by ovine abortion with fetal anomalies in Nineveh province, Iraq

Abstract

In late 2011, Schmallenberg virus (SBV) was observed in Germany using genomic analysis. The virus is transmitted through insect vectors and vertically from females to their offspring across the placenta. In adult sheep, the virus causes a short viremia followed by lethargy, abortion, and dystocia when giving birth to malformed lambs. RT-PCR for virus detection and commercial ELISAs for antibody detection were rapidly developed. No previous studies have detected SBV in sheep in Nineveh province. Thus, this study intended to investigate the presence of SBV in aborted fetuses and describe the macroscopic lesions. Fifteen aborted lambs aged between 70 to 135 days were collected between October 2021 and January 2022. Brain stem, spinal cord, spleen, liver, lung, and abdominal fluid were collected and stored at -20ºC for molecular analysis. Viral RNA was extracted from these collected samples, and reverse transcription was performed in one step. RT-PCR was applied to amplify the SBV gene (S segment). Three of fifteen lambs showed marked malformations in the vertebral column, arthrogryposis, hydranencephaly, cerebral and cerebellar hypoplasia, and porencephaly. SBV was detected in malformed aborted lambs by RT-PCR with 474bp product size. These findings indicate that SBV causes abortion with malformations. Further studies on this topic should include the isolation and characterization of the virus and SBV epidemiology.