Wetenschap - 19 december 2011

New virus causes deformities in livestock

A hitherto unknown virus causes lambs to be born with deformities and cows to have diarrhoea. Experts are worried that even the calves of infected cows will be born with deformities. Four questions for the Central Veterinary Institute (CVI).


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What virus is this?
It will be called the 'Schmallenberg virus', named after the German town where the virus showed itself for the first time in November. But the virus has been going around in Europe for some time. The CVI tested fifty cows with bovine diarrhoea at the end of August but did not find any virus in their dung then.  This month, the CVI tested the blood of the cows after the virus was discovered in Germany and found that 18 of them have been infected with the virus.
How did the virus reach here?
The virus is most likely spread through the midge, a small mosquito also responsible for spreading the bluetongue virus in the Netherlands. But the two viruses are not related, says CVI researcher Wim van der Poel. Parts of the genome of the new virus have been identified. These show that it is related to the Akabane virus and the Shamonda virus, found in Asia and Africa respectively, where they affect the foetuses of cows and sheep. The new virus is, however, not identical to these two. 'It looks like a new combination,' says Van der Poel. In the coming week, the CVI will carry out more studies into the new virus.
How many cows and sheep are carriers of the virus?
This is what the CVI and the Animal Health Service (GD) will try to find out. They will first reconstruct the way the virus spread. The number of affected sheep will become known next month when the majority of lambs will be born. In February, the spread among the cows will become apparent when the majority of calves will be born.
Is there a cure?
First, the genome of the new virus has to be known. Afterwards, the CVI can develop a vaccine. But vaccine development takes at least a year, says Van der Poel.