Schmallenberg virus was first reported in in cattle the summer of 2011 near the town in Northern Germany that gives it its name. Since then, the spread of the virus has been rapid. In the UK, it was first reported on 11 farms in January 2012, and has grown month-on-month since then. It is spread by midges (Culicoides), and so can easily be transferred between animals. It has also been found in wild deer, which could be a reservoir of infection.
It causes stillbirths in lambs and calves, and fever, reduced milk yields and loss of appetite in adult cattle. Schmallenberg virus has now been confirmed at over 1500 farms in the UK, and has been detected throughout northern, central and eastern Europe.
Cases of Schmallenberg have now been reported in all parts of England, Wales and Northern Ireland. This has put Scottish farmers on high alert for the disease, which is carried by midges, and could thus cause havoc in the Scottish Highlands.
Joanne Pugh, of the National Sheep Association, spoke to BBC news and was keen to stress that "as an overall picture across the whole sheep flock it’s a low impact disease”, however she also did point out that for the affected flocks the disease is devastating.
The key to tackling this disease will be to gather more data on the virus and its epidemiology – and this is precisely what several animal health groups are attempting to do.
However, there is already information available. As veterinary expert at CABI Robert Taylor points out, “With a new disease like SBV much can be learned about potential risks, epidemiology, and control strategies from our knowledge of its relative, Akabane virus, and from the behaviour of the midge that transmits the virus.”
Taylor highlighted that the CAB Abstracts Database already has 156 records on Schmallenberg virus, and 550 on the closely related Akabane virus. The database also has a vast amount (4450 records) on the Culicoides vector.
This information could be key in predicting the impact of the virus, understanding its workings, and developing strategies to manage and control it.
Whilst Schmallenberg virus will continue to affect herds and flocks for some time yet, work to develop a vaccine is well underway. Understanding the cost-benefit analysis of control strategies for a new disease is a challenge. Using a combination of research and data collection, and an examination of the information already available, the virus may yet be controlled.
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