27 June 2007

3 minute read

Europe

Professor Peter Mertens, Head of the Arbovirus Research Group at the Institute for Animal Health, commented “Re-emergence of the virus in northern Europe may increase the risk that bluetongue virus could spread to the UK this year.”

“The findings in Germany suggest that the virus may have survived through the winter.” Professor Mertens said “Farmers and veterinarians in the UK should remain vigilant for clinical signs that might be caused by bluetongue virus.”

The German veterinary authorities had placed bluetongue-free cattle amongst some herds that had the disease last year. Laboratory analysis of samples collected sequentially over the last few months have led scientists to conclude that the virus spread to a previously virus-free animal during April.

Bluetongue occurred for the first time ever in Germany, Belgium, France, Luxembourg and the Netherlands last summer, and established a major focus of infection on the coast of Belgium, close to the UK. All ruminants can become infected, and cattle are more susceptible to infection than sheep.

Bluetongue virus is spread by biting midges. “Infected midges can be spread large distances by the wind, like aerial plankton, taking the virus with them” said Peter Mertens. The UK is most at risk when there are easterly winds that could blow infected midges from continental Europe to our south-eastern counties.

“Essex, Kent and East Anglia are most at risk.” said John Gloster, of the Met Office, seconded to the Institute for Animal Health. “Easterly winds from the near continent can be expected to blow towards these counties four to seven days each month during May to October.”

“With the recent case of the virus in Germany being many hundreds of kilometres away from our east coast, the risk of infected midges being carried on the wind to the UK is currently assessed as minimal. However, if outbreaks were to be reported near to the west coast of the near continent then the risk to the UK would increase. A very close watch is being kept on both the disease situation and meteorology. Defra are updated on a daily basis.” said John Gloster.

Professor Mertens said “Farmers and veterinarians in the UK should remain vigilant for clinical signs that might be caused by bluetongue virus.”

The disease first occurred in northern Europe last summer. The virus grows much better in the midges when the ambient temperature (and hence the temperature of the midges) is high, as is normally the case where bluetongue is usually found (on several continents, in latitudes between southern Spain and southern Africa). Last summer in northern Europe there were periods of exceptionally high (record) temperatures that would have favoured the spread of the virus.

From the 14th to the 16th of April this year, in the region of the German farm where the virus has re-emerged, a temperature of 28°C occurred. This may have contributed to the re-emergence of the virus

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