RAPID RISK ASSESSMENT New bornavirus strain detected in the EU

Consulted experts Experts from ECDC: Hervé Zeller, Dragoslav Domanović, Celine Gossner, Denis Coulombier. External experts: Martin Beer, Paula M Kinnunen, Olli Vapalahti, Dennis Tappe, Jonas Schmidt-Chanasit, Bernd Hoffmann. Main conclusions and options for action A recently reported cluster of acute fatal encephalitis in three squirrel breeders possibly related to an infection with a newly identified bornavirus is an unusual event. The novel nature of this occurrence requires that additional investigations are undertaken into the role of a new bornavirus in the aetiology of these cases, the identification of natural hosts, reservoir and the transmission route. Nevertheless, pending the completion of the cluster investigation, it is advised that feeding or direct contact with living or dead variegated squirrels should be avoided, as a precautionary measure. Further investigations are ongoing to characterise these cases. In addition, testing of cases of human encephalitis for this newly identified bornavirus, especially in areas where the presence of bornavirus is documented in animals, can contribute to a better understanding of the risk of bornavirus infection in humans. RAPID RISK ASSESSMENT