The number of cases of Schmallenberg virus has risen to 2,126 in Europe. The infection has been has been identified on 158 farms in England, according to the AHVLA’s latest update on the SBV situation, released yesterday. 

The AHVLA said 11 of the positive cases have been diagnosed in cattle and 147 in sheep, though to date no other animals have been affected in Britain; in continental Europe other ruminants, including bison and goats have been affected. There has been no increase in the spread or number of counties affected by the virus, which has affected farms from the South West to the East Midlands.

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Elsewhere in Europe, the effects of Scmallenberg continue to be felt. Veterinary scientists from Europe’s Veterinary science and research institutions continue to work together to monitor Schmallenberg. Nevertheless, more infections are still coming to light, as the calving and lambing seasons progress.

In Germany, where SBV was first identified, the virus has affected 923 farms, in France 660, Belgium 213 and the Netherlands 162. The virus has also been identified on farms in Luxembourg and Spain.  

The disease causes flu-like symptoms in cattle, but is symptomless in sheep. Although it appears to affect a herd for a period of a few weeks, if pregnant animals are infected the disease can lead to stillbirth and congenital abnormalities of their offspring. This disturbing element of SBV, combined with the fact that little is known for sure about the new disease, has caused great consternation amongst farmers, who are unsure whether the disease will ‘fizzle out’ or spread when midges become active this year.

Test in Netherlands show 70 per cent of cattle have Schmallenberg antibodies

In the Netherlands, The Central Veterinary Institute has developed a test which reveals whether animals have antibodies for Schmallenberg virus. Until now, only PCR tests have been available, which detected the virus in brain material of newborn animals. The test apparently gave much lower positive results for calves, though this new approach has revealed a much higher rate of infection.

The Dutch researchers, who tested dairy cows, said the high prevalence of antibodies against Schmallenberg virus in the dairy cattle population, which was found to be around 70 per cent, indicates widespread exposure to the virus has occurred. They said this means the number of suspected cases in cows may be an underestimate, not only in the Netherlands, but throughout infected countries.

In 1974, when the Akabane virus, which belongs to the same group as Schmallenberg virus, affected Australia, prevalence was shown at 80 per cent following an outbreak in New South Wales.

The researchers said it remains too early to draw conclusions from their findings, although in an ideal scenario it could mean infections drop as a result of widespread development of antibodies. Earlier this month, Liverpool University’s Matthew Baylis told delegates at a conference on Schmallenberg virus that the disease may “fizzle out”, as infected animals appear to become immune to the virus after infection, there is no evidence for animal to animal transfer occurring and midge populations may no longer be infected. However, as the disease was first discovered less than a year ago, it may still be too early to speculate.

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