Brussels, 20 Apr 2006
British scientists investigating bluetongue disease have appealed for regional farmers to help them in their quest for new ways to track the disease.
Bluetongue is a virus spread by the midge - a tiny biting insect. It can be spread to sheep, goats, buffaloes, deer, antelope and camels. However, most European farmers will naturally be concerned about the potential effects on sheep and goats. The disease causes the infected animal to run a fever, salivate profusely and develop a swollen tongue and lips. This last symptom often gives the characteristic blue tongue. The disease is not infectious to humans.
The disease is not normally fatal, although infected animals are slow to recover. Nevertheless, the virus has killed 1.5 million sheep in 12 European countries since 1998. The disease is usually kept in check through vaccinations, quarantine or the control of midges, but the current spread of the disease has been swift.
The new study will use satellite and environmental information to track the spread of the disease. Results should feed into methods of animal management throughout Europe. The disease is spreading rapidly in Southern Europe but drifting north, most likely due to global warming.
The UN's Food and Agriculture Organisation (FAO) lists Bluetongue in the List A disease category of the Office International des Epizooties (OIE): 'Bluetongue can cause spectacular disease outbreaks [...]. Affected sheep may die after acute or chronic disease, or may recover with weight loss and/or wool breaks.'
This study, funded by the UK's Biotechnology and Biological Sciences Research Council (BBSRC) and Department for Environment Food and Rural Affairs (DEFRA), will involve asking farmers to set light traps to catch the midges, which will then be analysed for instances of bluetongue.
The worrying spread of bluetongue is due to the transfer of the virus from one vector, Culicoides imicola - a midge native to North Africa but now becoming more prevalent in Europe, to two further vectors - Culicoides obsoletus and Culicoides pulcaris, both of which are native to Europe.
Dr Simon Carpenter from the British Institute for Animal Health (IAH) is one of the team leaders monitoring the spread of midges. 'We are looking at both the distribution of biting midges and their seasonal abundance,' he says. 'Putting these data together with images from weather satellites and using models that predict future climate, we will be able to identify areas and times of the year most at risk.'
The information from individual farms will feed into satellite images, permitting scientists to see whether it is indeed possible to track to progress of infected midge populations.