Resumen de Short communication: Exposure to Schmallenberg virus in Irish sheep in 2013

D. J. Barrett, S. J. More, R. G. O'Neill, D. M. Collins, C. O'Keefe, V. Regazzoli, D. Sammin

• MALFORMED fetuses attributable to Schmallenberg virus (SBV) were found in 49 cattle herds and 30 sheep flocks exclusively in the southern and eastern parts of Ireland (Barrett, D., More, S. J., O'Neill, R., Bradshaw, B., Casey, M., Keane, M., McGrath, G. & Sammin, D. (Submitted) Prevalence and distribution of exposure to Schmallenberg virus in Irish cattle during November 2012 to November 2013). National bovine serological studies late in 2012 and 2013 confirmed exposure to SBV was effectively confined to the south-east (Barrett and others, submitted). It was unclear whether the distribution of seroconversion in cattle reflected the situation in sheep. Several studies have shown that Culicoides species preferentially feed on cattle rather than sheep (Ninio and others 2011, Ayllon and others 2014, Elbers & Meiswinkel 2014), leading to lower levels of seroconversion in sheep flocks than in neighbouring cattle herds (Gache and others 2013). It was anticipated that SBV would continue to spread across the country over the second (2013) vector season, similar to the experience in mainland Europe (Garigliany and others 2012, Veldhuis and others 2013, Balmer and others 2014). The objectives of this study were to determine the geographical distribution of SBV exposure in Irish sheep before and during the 2013 vector season, and to determine if SBV was active in 2013 in flocks where SBV infection was previously confirmed.

  Two studies were conducted, each in different sets of sheep flocks. In the first study, serological samples were collected in 32 sentinel flocks sampled on two …