BBSRC funding at forefront of fight against livestock disease
Institute for Animal Health contributes to national response to Schmallenberg threat
27 February 2012
An emerging livestock disease caused by the Schmallenberg virus has been causing deformities in newborn lambs, goat kids and calves on farms in Belgium, Germany, the Netherlands, and now the UK. Schmallenberg - named after the place in Germany where the first sample of the virus was identified - causes deformities and still births but does not have major clinical signs in adult animals, making it quite difficult to spot. Scientists at the BBSRC funded Institute for Animal Health (IAH) are at the forefront of the national response and offer multidisciplinary expertise in animal health.
Schmallenberg is affecting mostly sheep in the UK, with a small number of cattle also affected. Image courtesy of Joost J. Bakker IJmuiden
Professor Peter Mertens, head of the Vector-borne Diseases Programme at the Institute for Animal Health said: "We are studying this disease and the virus that causes it in a number of ways. One major priority is to put in place reliable test systems, so that we can detect the genomic RNA of the virus and virus specific antibodies. This will allow us, to test and identify infected animals or insects."
Schmallenberg virus was first identified in the UK on 22 January 2012. It has now been identified on 74 farms. Cases have been identified in the Isle of Wight, Wiltshire, West Berkshire, Gloucestershire, Norfolk, Suffolk, Essex, Kent, East and West Sussex, Hertfordshire, Surrey, Hampshire and Cornwall. Five of the positive cases have been diagnosed in cattle, 69 in sheep, and none to date in other species. So far, none of the affected farms have reported importing animals during 2011 from the affected areas in mainland Europe.
The congenital defects that are being seen now are caused by infection of the pregnant ewes or cows late last year so there is nothing that can be done to prevent them. However, there is also the possibility that the virus has survived through the winter to cause future infections.
So far the disease has had only a limited impact in the UK, with cases found during early lambing, so it is difficult to say what percentage of lambs or calves are likely to be affected by the virus this year. Recent experience by veterinary colleagues in mainland Europe shows that up to 25 per cent of lambs born in a one infected flock had significant or severe congenital defects of their limbs or central nervous system.
It is currently thought likely, but not yet confirmed, that Schmallenberg virus can be transmitted by biting midges. IAH has colonies of midges and mosquitoes that will be used to confirm if the virus does indeed infect these insects, which are then transmitting it between animals.
Dr Simon Carpenter, research leader in entomology at IAH said: "Samples of the virus have arrived at Pirbright from colleagues in Germany. Using Insects from our colonies we will be able to see if midges or mosquitoes can become infected by Schmallenberg virus. This will allow us to tailor our advice to a wide range of stakeholders, including livestock owners who could be affected by the virus in 2012 and also to understand some of the factors driving the outbreaks."
If Schmallenberg is confirmed as a midge-borne virus, IAH's expertise and experience concerning the epidemiology of bluetongue virus will be invaluable. It was thanks to the combination of disciplines including virology, entomology, meteorology, and mathematics at the Institute that the arrival of bluetongue in the UK in 2007 was predicted, allowing for measures to be put in place to prevent a major outbreak - work that is estimated to have saved the UK economy £485 million. IAH and the Met Office are already collaborating in the planning stages of work concerning Schmallenberg virus.
Dr Simon Gubbins, IAH research leader in Mathematical Biology said: "If Schmallenberg is midge-borne - and it does look likely that it is - we can begin to learn more about how it is passed on. That helps us in two important ways: it means we can make predictions about how it might spread in the future and therefore consider whether there are suitable control methods which may lessen the impact. It will also tell us something about where it came from."
Professor Douglas Kell, Chief Executive of BBSRC, said: "While we don't know yet how seriously the UK and Europe are affected by this disease, we are well placed to respond. Experts in the UK are working to learn as much as possible about the detection and control of this virus and we have excellent resources to do this. We have invested in research that enables us to act quickly and smartly to minimise impact.
"The handling of the bluetongue outbreak in 2007 was a perfect example of taking control through thorough scientific understanding and it led to the prevention of a major outbreak and huge economic savings."
BBSRC continues to invest in national research infrastructure with the development of new high-containment laboratories and experimental facilities at the IAH campus at Pirbright. The new facilities for studying avian and other diseases will help to support the development of new vaccines and tests. This new investment will allow BBSRC and IAH to further the vision of founding an animal health science and innovation campus at Pirbright centred on world-leading research.
For background information on the Schmallenberg virus visit IAH at: www.pirbright.ac.uk/FrontStories/2012/Schmallenberg.aspx and the Animal Health and Veterinary Laboratories Agency: vla.defra.gov.uk/science/sci_schmallenberg.htm.