British midges can carry lamb virus

Common midges are likely to be spreading a disease that has caused thousands of lambs and calves to be born dead or deformed, scientists have found.Schmallenberg virus, which has caused devastation across Europe, has now been confirmed on 209 farms in southern and eastern England, with cases stretching as far north as Lincolnshire.Researchers in Belgium, where hundreds of farms have been hit since December, have found three species of midge that are likely to be responsible for passing the virus between animals.All three species - Culicoides obsoletus, Culicoides dewulfi and Culicoides pulicaris - are native to Britain. Culicoides obsoletus is one of the most abundant species found on farms in the UK and is also responsible for transmitting the Bluetongue virus, which caused widespread disease in livestock in 2007 when insects were blown across the channel.Officials at the Department for Environment, Food and Rural Affairs (Defra) have now confirmed that "it is likely that domestic midges have transmitted Schmallenberg virus within the affected areas".A spokesman said: "We cannot rule out the possibility that domestic [local] midges may have transmitted Schmallenberg virus within the affected areas. Domestic midges may have been infected after biting a local animal infected last summer after incursion of Continental midges."The finding from Belgium raises the prospect that the virus may have survived the winter in British insect populations and will continue to spread around the country through the spring and summer as insects become active again. The full impact of this will only become clear next year when the next round of lambs and calves are born, leaving farmers with a tense wait over the coming 12 months.Dr Simon Carpenter, from the Institute of Animal Health in Pirbright, Surrey, said: "The fact that virus genetic material has been isolated from these midge species is bad news for us in the UK as they are abundant on all of our farms.Researchers at the Institute of Tropical Medicine in Antwerp, Belgium, found genetic information from the virus in the heads of samples from the three species of midge, suggesting the virus was carried in their saliva and so could be transmitted.Experts at the Institute of Animal Health are now seeking to confirm whether it can be passed on to livestock from these midges. They are also aiming to discover whether the virus may be able to survive the winter in the eggs of midges or mosquitoes found in the UK. Together with meteorologists at the Met Office, they have also been modelling potential routes that may have brought the virus into Britain. The most likely theory is that plumes of infected midges were blown over the Channel from northern France and Belgium on several days during late October and early November. Winds on these days could have carried infected insects as far as South Wales.Schmallenberg virus causes lambs and calves to be born dead or with serious deformities, including fused limbs and twisted necks, which they cannot survive.The disease first started to emerge in August last year in Holland and Germany when adult cattle began showing signs of illness. Although mature animals quickly recover - adult sheep show no signs of illness - the virus can have devastating affects on the unborn offspring of pregnant livestock which form the next generation in a herd.As the virus appears to mainly affect the unborn offspring of animals that were pregnant when infected, the full scale of the outbreak in the UK will not become clear until later this year as the spring lambing season intensifies and the majority of calves are born in early summer.The worst hit farms in Britain have seen losses of 20 per cent, while on average British farms have seen around five per cent of their new animals being stillborn or born with deformities. Around 16?million lambs are born in Britain each year and sell at market for about pounds 100. There are more than 67,000 sheep farms in the UK.Peter Garbutt, the chief livestock adviser at the National Farmers Union, said: "It is concerning for farmers at the moment. The virus appears to be very fickle as some flocks are affected while others nearby are not. "Even within flocks we are seeing twins being born with one lamb seemingly healthy and the other affected."Currently no vaccine exists against Schmallenberg and researchers are working to produce one, although this may take up to two years.