Background Bluetongue (BT) is a viral disease of ruminants and camelids which can have a significant impact on animal health and welfare and cause severe economic loss. The UK has been officially free of bluetongue virus (BTV) since 2011. In 2015, BTV-8 re-emerged in France and since then BTV has been spreading throughout Europe. In response to this outbreak, risk-based active surveillance was carried out at the end of the vector seasons in 2017 and 2018 to assess the risk of incursion of BTV into Great Britain.
Method Atmospheric dispersion modelling identified counties on the south coast of England at higher risk of an incursion. Blood samples were collected from cattle in five counties based on a sample size designed to detect at least one positive if the prevalence was 5 per cent or greater, with 95 per cent confidence.
Results No virus was detected in the 478 samples collected from 32 farms at the end of the 2017 vector season or in the 646 samples collected from 43 farms at the end of the 2018 vector season, when tested by RT-qPCR.
Conclusion The negative results from this risk-based survey provided evidence to support the continuation of the UK’s official BTV-free status.
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Funding This survey was carried out by the Animal and Plant Health Agency and funded by the Department for the Environment, Food and Rural Affairs, Scottish Government and the Welsh Government. Simon Carpenter, Carrie Batten, John Flannery and Simon Gubbins are funded by BBSRC grants BBS/E/I/00007036, BBS/E/I/00007037, BBS/E/I/00007033 and BBS/E/I/00007038.
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Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request. Further information on the approach to this study may be requested but information on participating farms will not be made available. Requests may be made to Katherine.email@example.com.
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