7 September 2016

3 minute read

Europe

“According to DEFRA’s latest bluetongue situation assessment¹ there is currently a medium risk of an incursion of infected midges arriving in Britain from across the Channel, but a high risk by the end of the summer. Thankfully, bluetongue vaccine supplies are now readily available, so we are urging farmers to discuss their disease risk situation with their vet as soon as possible,” said British Cattle Veterinary Association (BCVA) Senior Vice President Gareth Hateley.

Mr Hateley says that if the bluetongue virus does appear in Britain once again, the most significant impact on the UK sheep and cattle sector would be the enforcement of restriction zones of at least 150km, from which susceptible animals would not be allowed to move to other parts of the country. “This would have significant implications for trade and animal welfare, so far better to take all available steps to try and prevent disease, rather than have to deal with an outbreak once it occurs,” he said.

Supplier of the BLUEVAC® BTV8 bluetongue vaccine MSD Animal Health points out that the vector-borne nature of bluetongue makes reducing the risk of animals coming into contact with the virus extremely difficult.

“You simply can’t guarantee that stock will not get bitten by infected midges. This is why it is so important that all animals at risk have the necessary level of immunity to prevent the disease breaking out, and why vaccination is the single most effective action you can take to protect your cattle and sheep,” said MSD Animal Health technical manager John Atkinson.

Vaccination has been proven to control bluetongue, but the success of a vaccination programme is reliant on a high proportion of cattle and sheep farmers vaccinating their stock, particularly across southern England.

“Widespread vaccination helped to prevent bluetongue gaining a foothold in Britain the last time the disease threatened our shores back in 2007/08. Experience of that outbreak in Northern Europe tells us though that if the virus is not effectively controlled within a naïve livestock population we are likely to see a dramatic increase in cases over successive seasons, with hundreds in the first season, thousands in the next and tens of thousands in year three. It’s just not worth the risk of not vaccinating,” Mr Atkinson says.

Mr Hateley adds that the results of a recent survey of bulk milk samples for antibodies to BTV8 taken from 200 dairy herds in the south and east of England should be interpreted with caution.

“A high proportion (>80%) of the herds in this study did test seropositive for antibodies to the bluetongue virus; most likely due to historical vaccination and/or historical infection. But these findings should not be interpreted as an indication that seropositive herds will be immune to the disease this time around: each positive bulk milk result could have been caused by just one or only a few animals in the herd having antibodies. The herds are likely to have little immunity if the cattle remain unvaccinated,” he warns.

“What we do know though is that the most effective control measure against BTV8 is vaccination, so we are urging farmers to talk to their vet as soon as possible,” Mr Hateley said.

^1. Bluetongue virus (BTV8) in France. DEFRA Updated Situation Assessment No.10 (21st July 2016)