In the coming weeks farmers in northern Europe will be counting sheep, but not to help them sleep. They are keeping a close eye on their flocks after the appearance of the bluetongue virus in sheep in the Netherlands. Transmitted by midges, the virus usually occurs in warm, wet areas, and has never been seen so far north.
The virus causes high fever and swelling of the tongue in ruminants, and can kill up to 30 per cent of infected sheep. 鈥淚t devastates sheep populations,鈥� says Walter Tabachnick of the University of Florida in Vero Beach.
Changes in Europe鈥檚 climate may mean the midges that carry the virus are more likely to survive the winter. 鈥淕lobal warming could theoretically change the distribution of bluetongue,鈥� says David Stallknecht of the University of Georgia in Athens. 鈥淵ou can control it with vaccination, but of course that costs money.鈥�
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