What is Schmallenberg virus?
Schmallenberg virus is a new virus, which caused acute illness in dairy cattle in Germany, the Netherlands and Belgium during the summer of 2011. More recently, it was found to have caused birth deformities in sheep, cattle and goats in the same countries. The first UK cases in lambs were detected in January 2012. Affected animals have been identified in many counties in east, southeast and southwest England.
How is this disease spread?
As this is a new virus, it is not yet known how it is transmitted. Schmallenberg virus belongs to a group of viruses that are spread by midges and mosquitoes. The affected UK counties were identified as potentially being at risk from infected midges blown across the Channel from the affected areas and this is thought to be the most likely route of transmission for the UK cases.
Are there any health risks to humans?
At the moment, a Europe-wide assessment has concluded that Schmallenberg virus is unlikely to cause illness in people. As yet, no human cases have been detected in any country, and the most closely related viruses only cause animal disease. However, as this is a new virus, work is ongoing to identify whether it could cause any health problems in humans.
How do I know if animals have this virus?
Acute signs in infected dairy cows include fever, poor general condition, anorexia and reduced milk yield (by up to 50%). Some animals also had severe diarrhoea. Signs of this acute illness disappeared after a few days and the animals appeared to recover unaffected. No acute illness was reported in sheep, and no illness was seen in adult animals after October. However, in early December 2011, high numbers of congenital (present at birth) malformations were seen in newborn lambs, many of which were stillborn. Malformations included twisted neck, abnormal curvature of the spine and limb contractures. Smaller numbers of deformed newborn calves and goats have also been reported. It appears that the mothers were infected with the virus during early pregnancy, and that the virus has caused these abnormalities.
How do I reduce the risk of infection with this virus?
While more work is being done to understand more about this virus, existing regulations and guidance on good farm practices should be followed as they can help to reduce the risk to human and animal health from many infectious diseases.