First detected in Germany in late 2011, the Schmallenberg virus (SBV) has since spread across Europe, reaching south-east England in January 2012 and Co Cork in the Republic by October 2012.
Symptoms of the virus, which is transmitted among ruminant animals by biting midges, include stillbirth or malformation of calves and lambs.
Trade restrictions have not been applied to live animals, meat or by-products from infected holdings, with the World Animal Health Organization ruling any risk posed to humans as negligible. Farms with positive cases in Ireland are not subject to any additional controls.
While only 33 clinical cases of SBV have been confirmed in the Republic to date, an Irish Department of Agriculture, Food and the Marine (DAFM) survey detected exposure on 150 livestock farms prior to the early lambing season reports.
Detected exposures largely mirror the positive cases by geographic distribution, focused on Co Cork and the south-east counties of Wexford, Kilkenny, Wicklow and Waterford, but also extending up to Sligo and along the border with Northern Ireland.
DAFM has issued guidance to farmers, and acknowledges vaccination as likely “to be an effective tool in control of the SBV infection”, once it becomes commercially available.
Meanwhile, this week, the University of Nottingham has published predictions of a “grim return this year” for SBV with potential losses “as high as 30% on some severely affected holdings”, based on the detection by virology experts of defects in early lambing flocks. Every country in England and Wales was affected by the virus in 2012.
Latest numbers supplied by Defra this month confirm positive cases on holdings totalling 906 in England, 61 in Wales, eight in Scotland and one in Northern Ireland.