The changing landscape of bluetongue in northern Europe

Bluetongue was historically a disease of the tropics and subtropics, but over the past 20 yr has emerged in temperate regions such as northern Europe. Multiple serotypes of bluetongue virus (BTV) have been introduced into northern Europe, with some becoming enzootic, most notably 3, 4, and 8 in France. This review describes the step-change in the occurrence of bluetongue across northern Europe with a focus on changes since the re-emergence of BTV-8 in France in 2015. Five countries in northern Europe are specifically discussed-Belgium, France, the Netherlands, the United Kingdom, and Switzerland. These countries have all been significantly affected by the widespread outbreak of BTV-3, which emerged in 2023. Here, the latest data on case numbers, disease and Culicoides surveillance, and the current state of play for each country are presented. The latest research into vector competence, transmission studies, and advances in vaccination and vector control, relevant to northern Europe, are summarized. Finally, climate change and globalization are critically examined as reasons for the epidemiological changes in BTV occurrence across Europe.