The OIE List A viral disease, bluetongue (BT), has re-emerged in southern Europe. The current epidemic is associated with remarkable spread of the major insect vector across the Mediterranean basin, transmission by novel vectors and overwintering further north than ever before. In this dynamic situation, the epidemiology of BT must be reassessed, and the livestock of northern Europe are considered to be at risk. This proposal aims to assess the nature of the risk, principally to the UK, focusing on expected outcomes should BT virus be introduced, how its impact can be minimized, and what viral molecular changes may underlie the re-emergence. The proposal builds on existing strengths at Pirbright, and adds a mathematical modeling dimension.
The primary focus is the OIE List A viral disease, bluetongue (BT), which has re-emerged in Europe in recent years[1,2]. The current epidemic, which has led to the deaths of > 0.5 million sheep, is associated with remarkable and rapid spread of the primary insect vector across much of the Mediterranean basin, transmission by additional, novel vectors, and viral overwintering in regions further north than previously seen. In this dynamic situation, where the livestock of Northern Europe including the UK are now considered to be at risk[3,4], the epidemiology of BT should be reassessed. This proposal aims to assess the level and nature of the risk, principally to the UK, focusing on expected outcomes should BT virus be introduced, how its impact can be minimized, and what molecular changes to the virus may underlie the re-emergence. The principal methodologies include measuring aspects of vectorial capacity in the UK; the development of mathematical and statistical models of the epidemiology of BT; analysis of epidemic data from affected countries in Europe; investigation of a recently-proposed overwintering mechanism of BT virus; sequencing studies of virus isolates; evaluation of specific control measures, including novel approaches to vaccination. Furthermore, the epidemiology of African horse sickness (AHS, also OIE List A) is very similar to BT and the outputs will be relevant to assessing the threat of AHS to UK equids. The proposal builds on many existing strengths and areas of work at Pirbright, and adds a significant mathematical modeling dimension.. Principal collaborations are aimed at supporting this plan for modeling at IAH (University of Oxford, Animal Health Trust (AHT), University of Cambridge), to supplement studies of the overwintering mechanism (Royal Veterinary College, RVC), to input additional entomological expertise (Natural Resources Institute, NRI) and to input into the AHS vaccinology component (AHT).