Case report: an atypical case of EBLV-1 infection in the long distance migrant bat Pipistrellus nathusii in mainland France.

BACKGROUND

Over the past five decades, nearly 1,500 bat rabies cases have been reported in Europe. The majority of positive cases (with 90% of cases) originated from Germany, followed by The Netherlands, Denmark, Poland, France and Spain. Among the seven lyssaviruses detected in European bats, three different recognized species are circulating in some native bat species in France: EBLV-1, BBLV, and LLEBV, primarily associated with the host species Eptesicus serotinus, Myotis nattereri, and Miniopterus schreibersii, respectively. CASE PRESENTATION: In 2022, we reported an unusual case of EBLV-1 infection in a long-distance migrant bat species, Pipistrellus nathusii. The bat’s brain tested positive for the presence of viral antigens using the fluorescent antibody test (FAT) and for viral RNA through molecular techniques (including real-time and end-point pan-lyssavirus RT-PCR). In this study, we determined the nearly complete genome sequence of the virus using next-generation sequencing (PX733926). Molecular clock dating and phylogenetic analysis confirmed that the bat was infected with the EBLV-1a variant, the most common and widely distributed European bat lyssavirus. The virus genome showed 99.88% nucleotide similarity with a strain isolated from a serotine bat in the Lower Saxony region of Germany in 2016 (OU524432).

CONCLUSIONS

This finding is the first of its kind in France and the third in Europe involving a long-distance migrant bat. It may partially explain the extensive geographic distribution of EBLV-1a across Europe, following both east-west and north-south axes.