PAUL Roger's letter on assessing the risk of spread of Schmallenberg virus (SBV) ( VR , July 21, 2012, vol 171, p 77) was timely as I was on the cusp of being able to announce an update to Defra's continuing support to the development of our understanding of this virus. As Mr Roger recognises, the European Food Safety Authority (EFSA), having collected data on the same parameters from all affected EU member states, considers SBV to be of low impact: 3745 holdings found positive from a possible 1.15 million holdings in the eight affected member states, with variable regional effects from as low as 0.01 per cent of holdings to a maximum of 7.6 per cent of sheep premises in one region of Germany. Since the disease was first detected in August 2011, it has spread rapidly across northern Europe, in what was clearly a naive population. In addition, the EFSA …