Science - January 12, 2012

Schmallenberg virus may have been around some time

The new disease that reared its head in the German village of Schmallenberg in November has probably been around in Europe for some time, says CVI researcher Wim van der Poel. He reckons the disease, which causes deformity in lambs, is carried by the midge.

State secretary Bleker visits an affected farm.
The same insect spreads the bluetongue virus in the Netherlands. Van der Poel thinks it is significant that the Schmallenberg virus is affecting farms right across the country. Normally a virus spreads slowly across a region. This suggests that the virus was already present during the gestation period in the warm autumn of 2011, and that it was present in the midges before that, says Van der Poel. He now wants to check for the Schmallenberg virus in the midges caught last summer for testing for bluetongue.
New test
The Schmallenberg virus has already been found on 51 sheep farms and 1 goat farm in the Netherlands. Experts from the Central Veterinary Institute (CVI) fear that this may be the tip of the iceberg. The number of suspect farms where deformed lambs have been born has risen to 125. They include about fifty beef cattle farms. The virus has not been identified on all farms, by any means, but that does not mean that the pregnant sheep have not been infected. The CVI developed blood tests for identifying the antibodies for the virus in the animals' blood. These tests, the first version of which should be ready at the end of this month, can establish the scale of the contamination more precisely.
The CVI is collaborating with the German Friedrich Löffler Institut which identified the virus in November. Between them, they are mapping the genome of the virus, which should help to clarify which known animal disease the virus is related to, and speed up the manufacture of a vaccine. This will certainly take a year, says Van der Poel, because the vaccine's effectiveness has to be thoroughly tested.
In Belgium about fifty sheep have also tested positively for the virus. In Germany a calf is infected but very few sheep. ‘In Germany most sheep are inseminated later than in the Netherlands, after September. The midge season was over by then.'