Science & Environment

Farm virus 'can infect wild animals'

Image caption The virus causes birth defects in lambs

A livestock virus sweeping through British sheep flocks and cattle herds has infected wild deer, say scientists.

The disease, which is spread by insects, causes birth defects in lambs and can reduce milk yields in cattle.

Outbreaks have been reported in farm animals in Belgium, France, Germany, Italy, Luxembourg, The Netherlands, Spain and the UK.

European scientists say wild deer can catch the virus, and are calling for the impact on wildlife to be monitored.

Dr Mutien-Marie Garigliany, a veterinary expert at the Universite de Liege is one of a team of experts studying cases of Schmallenberg virus (SBV) in wildlife in the south of Belgium.

Dr Garigliany said wild animals such as roe and red deer can potentially act as a reservoir of infection.

"We should implement specific surveillance of wild animals for SBV," he told BBC News.

He said wild boar as well as wild deer show signs of SBV infection, although it is not thought to make them sick.

SBV first appeared in south east England more than a year ago, but has now spread to every county in England and Wales.

Dr Rachael Tarlinton, a virology expert and veterinary scientist at the University of Nottingham, said the disease was having a huge financial impact on some farms.

Lambing season

Reports from veterinary students at the university suggest losses as high as 30% of lambs in some infected flocks.

Image caption Red deer can catch SBV

Dr Tarlinton said the studies in Belgium show wild deer can catch the virus, but the impact on deer - and their offspring - is unknown.

"We know deer get the virus - they produce antibodies to it," she told BBC News.

"But deer have a different placental structure to cows and sheep - so we don't know if it gets across the placenta to affect foetuses."

According to Prof Trevor Drew of the UK government's Animal Health and Veterinary Laboratories Agency, the virus can infect native red deer, fallow deer, sika deer and roe deer.

The disease is transmitted by bites from midges and other insects, which makes it impossible to eradicate from British farms, Prof Drew told MPs last week.

"It is just impossible to control midges across an area the size of Europe," Prof Drew told the Environment, Food and Rural Affairs select committee.

"Even if we had some national campaign, it would be quite simple that the midges would be blown over and of course we cannot control the disease in wild deer."

The UK's deputy chief veterinary officer, Alick Simmons, said a vaccine against SBV is not yet available but several are being developed.

"This is a disease which we believe will either through vaccination or through natural spread become less of a problem over time," he told the committee.

"And already in the areas we have been affected in northern Europe and to a certain extent in the south east of England, the disease is less than it was last year."

Emerging disease

SBV, named after the German town where it was first detected, is an emerging livestock disease in Europe.

It was found in south east England early in 2012, and has since spread to every county in England and Wales.

SBV is not a notifiable condition, suggesting official figures on the number of outbreaks are a vast underestimate.

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