[Emerging vectorial diseases: West Nile fever, Bluetongue and Schmallenberg].

The increase in international trade over the last thirty years, climate change owing to the industrial revolution, disruption of ecosystems, etc. are some of the factors that may explain the dynamics of disease emergence in regions of the world where they were not present. Thus in 1999, West Nile virus was introduced on the American continent where it spread at high speed. More than 2300 deaths and more than 25,000 neuroinvasive forms were recorded in humans from 1999 to 2019 in the United States of America. In the field of animal diseases, two viruses have made headlines in Europe: bluetongue virus (BTV) and Schmallenberg virus (SBV). The bluetongue virus, previously absent from Europe, was introduced in 1999. Numerous serotypes (1, 2, 4, 6, 8, 9, 25, 27) have since been identified in the European Union. Schmallenberg virus was identified in 2011 in Northern Germany and rapidly spread to other European countries. This virus had never been identified in the world before. These three viruses (WNV, BTV and SBV) are transmitted by arthropod vectors (mosquitoes and Culicoïdes). These emergences are a good illustration of the challenges that our countries will face in the coming years, in public, human and veterinary health.