A bulk milk tank study to detect evidence of spread of Schmallenberg virus infection in the south-west of Ireland in 2013

BACKGROUND Schmallenberg virus (SBV) was first detected in Germany in November 2011. Confirmation of infection in Ireland was reported on October 30(th) 2012. The results of a national serological survey carried out in early 2013 suggested that the first introduction of SBV into Ireland probably occurred in the south or southeast of Ireland in the spring or summer of 2012, with subsequent spread eastwards and northwards. It was unclear at that stage whether the virus had survived the winter period and would continue to spread in 2013. The purpose of this study was to monitor the spread of the virus in the mid-west region through the summer and autumn of 2013 using bulk tank milk from selected dairy herds. FINDINGS Seventy two dairy farmers were recruited to participate in the bulk milk tank study. Each farmer agreed to collect a bulk tank milk sample on a weekly basis from early June. A total of 988 samples were received between June 5(th) and December 3(rd) 2013 and these were analysed using an indirect ELISA test. Of the initial set of 72 samples received between June 5(th) and July 16(th), nine were positive, one was inconclusive and 62 were negative. By the end of the study in early December 2013 only one new farm turned positive. This was the farm that had initially tested inconclusive. CONCLUSION The study results suggest that the anticipated spread of SBV across Ireland from the south and south-east did not occur during 2013.