More than 800 German farms have been hit by a new livestock disease that causes deformities in animals at birth, agriculture authorities said Friday.
Most of the 820 farms where the so-called Schmallenberg virus has been detected raise sheep, but cattle and goats are also affected, the Friedrich Loeffler Federal Research Institute of Animal Health said.
On February 1, the institute said that 186 farms in Germany had been hit, up from 51 five days earlier.
Believed to be carried by gnats and named after the German town where it was first detected, Schmallenberg causes fever and diarrhoea in adult livestock and cannot be transmitted from one animal to another, experts say.
It can however be transmitted to sheep, goat and cow embryos, leading to stillbirths or deformities causing death soon after birth.
The institute said it believed the first infections dated to mid-2011 and stressed that the virus was not transmissible to humans.
However, the Robert Koch Institute said it had undertaken a study to check that no humans had been infected.
"We have asked sheep breeders for blood samples which are being analysed," spokeswoman Susanne Glasmacher told AFP.
"We've also addressed a questionnaire to them to find out if they had particular symptoms. But the first results reveal no illness, no fever or any particular health problem," she added.
She said the test results would have to be known first before drawing any conclusions, however.
The virus, first identified in November, has been detected in Belgium, Britain, The Netherlands, Italy and France.
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