Schmallenberg virus is a midge borne arbovirus that first emerged in the European ruminant population in 2011 and has since settled to an endemic pattern of disease The impacts of trade restrictions on genetic products (semen, embryos) from affected areas were severe, particularly after the discovery that the virus is intermittendly shed in the semen of a small number of bulls. The trade in small ruminant (ram and goat) semen is less than that of bulls, nonetheless there has been no study into the shedding rate of SBV in ram semen.
This study tested semen samples (n=65) collected as part of UK ram trials and artificial insemination studies around the period of the 2016-18 Schmallenberg re-circulation. Semen was preserved in RNAlater for shipping with RNA extraction and S gene RT-qPCR performed for Schmallenberg virus nucleic acid detection
No Schmallenberg Virus Virus RNA was detected in any samples.
While larger numbers of animals would be needed to completely exclude the possibility of SBV shedding in ram semen this trial nonetheless highlights that this is likely a very rare event if it occurs at all and is unlikely to play a role in disease transmission.
Curwen, A., Jones, S., Stayley, C., Eden, L., McKay, H., Davies, P., …Tarlinton, R. (2022). Failure to detect Schmallenberg Virus in ram semen in the UK (2016-2018). Veterinary Record Open, 9(1), Article e39. https://doi.org/10.1002/vro2.39