Schmallenberg virus is spreading north very quickly, according to vet Fiona Lovatt. “There have even been deformed lambs born during the month of May, which tells us infected midges were active in December and January. And we know that a midge can carry 10 times more Schmallenberg virus compared with bluetongue.”
Immunity to Schmallenberg is very variable, farmers were told. There was an assumption that once a flock had suffered from the disease about 90% of that flock would be protected. But further studies in Germany and Holland have shown that figure to be much lower – around 36%. “It’s very difficult to talk about levels of protection after sheep have been infected because we still know very little about the disease, but it’s looking like at least 50% of sheep affected are still at risk from the disease in future years.”
Sheep can now be vaccinated against Schmallenberg virus from four months old and will be fully protected after three weeks. So far the advice is not to vaccinate in-lamb ewes and breeding tups.
“Sheep producers considering vaccinating against the disease should talk to their vet well ahead of tupping time,” advised Dr Lovatt.
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