Emergence of bluetongue virus serotype 4 in mainland France in November 2017.

Abstract: In November 2017, a 15‐day‐old calf located in France (Haute‐Savoie department) was found positive for bluetongue virus (BTV) RNA by RT‐PCR. Laboratory investigations allowed the isolation and identification of the serotype: BTV‐4. The analysis of the full viral genome showed that all the 10 genome segments were closely related to BTV‐4 strains involved in a large BT outbreak in the Balkan Peninsula, in Italy since 2014 and in Corsica since the end of October 2016. These results together with epidemiological data suggest that BTV‐4 has been introduced to mainland France from Corsica or Italy where BTV‐4 outbreaks have been reported in summer and autumn 2016. This is the first report of the introduction of BTV‐4 in mainland France. [ABSTRACT FROM AUTHOR]