Schmallenberg Virus Neutralising Antibody Responses in Sheep

Jones, Scott; Eden, Laura; McKay, Heather; Bollard, Nicola; Dunham, Stephen; Davies, Peers; Tarlinton, Rachael

Abstract

Schmallenberg virus (SBV) is a midge borne virus of cattle and sheep. Infection is typically asymptomatic in adult sheep but fetal infection during pregnancy can result in abortion, stillbirth, neurological disorders and malformations of variable severity in newborn animals. It was first identified Germany and the Netherlands in 2011 and then circulated throughout Europe in 2012 and 2013. Circulation in subsequent years was low or non-existent until summer and autumn 2016, leading to an increased incidence of deformed newborn lambs and calves in 2016-17. This study reports SBV circulation in October 2016 within a group of 21 ewes and 13 rams. The ewes were monitored at 3 times points over an 11 week period (September to December 2016). Most ewes displayed an increase in SBV VNT with antibody titre increases greater in older, previously exposed ewes. Two ewes had SBV RNA detectable by RT-qPCR, one on 30/09/16 and one on 04/11/16. One of these ewes had detectable serum SBV RNA (indicating viraemia) despite pre-existing antibody. The rams had been previously vaccinated with a commercial inactivated SBV vaccine, they showed minimal neutralising antibody titres against SBV s 8 months post-vaccination and all displayed increased titre in October 2016. This data suggests that SBV circulated for a minimum period of 5 weeks in September to October 2016 in central England. Ewes previously exposed to virus showed an enhanced antibody response compared to naïve animals. Pre-existing antibody titre did not prevent re-infection in at least one animal, implying immunity to SBV upon natural exposure may not be life-long. In addition, data suggests that immunity provided by killed adjuvanted SBV vaccines only provides short term protection (

Citation

Jones, S., Eden, L., McKay, H., Bollard, N., Dunham, S., Davies, P., & Tarlinton, R. (2019). Schmallenberg Virus Neutralising Antibody Responses in Sheep. BMC Veterinary Research, 15, https://doi.org/10.1186/s12917-019-2139-7

• Journal Article Type: Article
• Acceptance Date: Apr 25, 2019
• Online Publication Date: Nov 28, 2019
• Publication Date: Nov 28, 2019
• Deposit Date: Jul 2, 2019
• Publicly Available Date: Dec 3, 2019
• Journal: BMC Veterinary Research
• Electronic ISSN: 1746-6148
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 15
• Article Number: 426
• DOI: https://doi.org/10.1186/s12917-019-2139-7
• Keywords: General Veterinary; General Medicine
• Public URL: https://nottingham-repository.worktribe.com/output/2257615
• Publisher URL: https://bmcvetres.biomedcentral.com/articles/10.1186/s12917-019-2139-7
• Additional Information: Received: 27 April 2018; Accepted: 25 April 2019; First Online: 28 November 2019; : All blood sampling procedures were carried out as authorised by the UK Home Office under the ‘Animals (Scientific Procedures) Act 1986’ (licence no. PPL 30/3367). The Licence was granted to RT at the School of Veterinary Medicine and Science, University of Nottingham approved by the University of Nottingham Animal Welfare and Ethical Review Body (AWERB).; : Not Applicable; : The authors declare that they have no competing interests.