Detection of BBLV in Natterer’s bat in Poland

Abstract

Rabies is a zoonosis caused by RNA viruses belonging to the genus Lyssavirus, which includes 16 species. In Europe, the majority of rabies cases in bats are caused by European bat 1 lyssavirus (EBLV-1) associated mainly with serotine bats (Eptesicus serotinus and Eptesicus isabellinus). In 2010, Bokeloh bat lyssavirus (BBLV) was detected in Natterer’s bat (Myotis nattereri) in Germany and it was isolated several times in Germany and France in the following years. As required by the programme of passive rabies surveillance, the dead bat was sent to the laboratory and identified as Natterer’s bat on the basis of morphological criteria, which was confirmed by genetic identification using the sequencing of the cytochrome b gene. Brain tissue and salivary glands were collected for examination. In the brain, the direct immunofluorescence test revealed lyssavirus antigen. The presence of the infectious virus in brain tissue was confirmed by a tissue culture inoculation test. High levels of viral RNA were found in the brain and salivary glands. In order to determine the virus species, a complete genome sequence was obtained by next-generation sequencing of RNAs. The analysis of the full virus genome sequence confirmed the occurrence of BBLV in Poland and revealed that it showed the highest similarity (99.3%) to German isolates from Bavaria.