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Scientists call on farmers to help prevent spread of severe animal disease

5 April 2006

Scientists studying the potentially devastating animal disease, bluetongue, are calling for the assistance of farmers to help them understand the distribution of the potential carriers, certain species of Culicoides biting midges, across the UK.Biting midges

Although bluetongue has not been recorded in the UK, the last eight years have seen it spread throughout much of southern and eastern Europe and climate change is allowing it to extend into more northerly areas than ever before. Recent outbreaks have seen the virus that causes bluetongue being carried by different species of midge which are known to be prevalent in the UK. Researchers funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and Defra are calling for farmers to let them set up light traps to run overnight on agricultural land around the country. The biting midges caught in the traps can then be analysed to identify their species and to determine their capacity to spread bluetongue virus.

Dr Simon Carpenter from the BBSRC-sponsored Institute for Animal Health (IAH), explained: “We want to better understand both the distribution of biting midges and their seasonal abundance. Using light traps to understand where the hotspots of midge activity are, and combining this with information from weather satellites and climate change models, we will be able to predict the areas of the UK and times of year most at threat from bluetongue if it does arrive here.”

Bluetongue is caused by a virus that can reproduce in all species of ruminant. This means that animals unaffected by the disease, such as cattle, can be covert carriers of the virus, infecting more livestock. In its severe form bluetongue most often affects sheep and some species of deer and can result in respiratory problems, swelling, fever and death. The research team at IAH are world leaders in understanding bluetongue and were the first to highlight its recent spread into southern Europe.Sheep bluetongue sampling

Temperature and rainfall are key variables in the ability of the carrier midges to breed and spread the virus. Below about 8-10 degrees Celsius development of adult midges is inhibited but on warm summer nights (18-29 degrees Celsius) the midges are much more active. Studies have even found the virus can lay dormant for up to a month in midges when the temperature falls below 10 degrees Celsius, becoming active when temperatures rise. If winters become shorter with global warming the midges and hence the virus may not be killed off. Midges require semi-aquatic breeding sites so rainfall is important in understanding disease transmission.

The team want to use the data gathered from farms as the first step to advising livestock farmers on the most effective preventative methods. Professor Philip Mellor, also from IAH, said: “If we can establish when during summer and autumn and under what weather conditions midge populations are best able to spread bluetongue virus we can use satellite images to predict which farms are most at risk and when they are most at risk. We are also analysing how insecticide usage or changing the management of livestock could help to prevent the spread of the virus by preventing animals being bitten by midges in the field."

ENDS

Notes to editors

This story appears in the April 2006 edition of Business, the quarterly research highlights magazine of the Biotechnology and Biological Sciences Research Council.

The research forms part of an integrated BBSRC/Defra funded project led by the Institute for Animal Health and including the Universities of Oxford and Cambridge and the Animal Health Trust.

Bluetongue is caused by a double-stranded RNA-virus. It is spread by a species of Culicoides (biting midge) which are found across Europe and feed on all livestock species and humans. The midges can be carried over land and sea by the wind. Previously it was thought that transmission of Bluetongue was caused only by an Afro-Asiatic species of midge (C. imicola) but more recently it has been found to be carried by more northerly species of midge native to the UK.

About BBSRC

The Biotechnology and Biological Sciences Research Council (BBSRC) is the UK funding agency for research in the life sciences. Sponsored by Government, BBSRC annually invests around £380 million in a wide range of research that makes a significant contribution to the quality of life for UK citizens and supports a number of important industrial stakeholders including the agriculture, food, chemical, healthcare and pharmaceutical sectors. http://www.bbsrc.ac.uk

External contact

Dr Simon Carpenter, Institute for Animal Health

tel: 01635 577241

Professor Philip Mellor, Institute for Animal Health

tel: 01635 577241

Contact

Matt Goode, Head of External Relations

tel: 01793 413299

Tracey Jewitt, Media Officer

tel: 01793 414694
fax: 01793 413382