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Schmallenberg Virus

Recently a few of our sheep clients had the unpleasant encounter with Schmallenberg virus.

In most cases it meant lambing problems due to deformed dead lambs, or alive lambs hardly able to survive due to deformation.

But also at some dairy clients we could prove the contact/exposure to the disease, where the main concern was drop in milk yield and possibly scouring.

Just to refresh: Schmallenberg is a virus which is believed to be transmitted by biting insects (midges, mosquitoes). The infection of a pregnant ewe during a certain stage of pregnancy can cause deformations in the foetus (born dead or alive), e.g. bent limbs and fixed joints, twisted neck or spine, shorter lower jaw but also some animals are born with a normal outer appearance but have nervous signs such as a "dummy" presentation or blindness, ataxia, recumbency, an inability to suck and sometimes convulsions. The main aspect is the time of infection, which is the reason why the amount of deformed lambs can be higher or lower.

Main infection source seems to be the blood. Research work suggests that live infected animals have the virus in their blood stream for two to five days. Nevertheless virus could also be proven in placenta and birth products!

Just a small reminder: ALWAYS dispose safely of placenta and all birth products after abortions or in this case deformed lambs!

Sheep seem to express the infection worse than cattle but even deformed alive/dead calves are possible!

At least there is no proven danger to humans yet. A small study in Germany couldn't prove any antibodies in humans which means no infection.

To confirm the diagnosis, best is to bring the whole foetus to the VLA where they can test for the virus. In dairy herds a bulk milk sample can be tested for antibodies (which would just confirm exposure to the virus). The milk test is done at a different lab so best to bring the samples to us.

Fortunately there will be a vaccine on the market soon, though it will be too late for most of this years lambing ewes so it's the unfortunate game of "wait and see" for all of us this time!