Combining host genetic structure and serology to investigate
rabies-related lyssaviruses in the greater mouse-eared bat (Myotis
myotis)
Abstract
European bat lyssavirus 1 (EBLV-1) is widespread and frequent in
European bats, particularly of the genus Eptesicus. However, other
species can be seropositive, suggesting a complex ecology still mostly
unknown. In Italy, EBLV-1 antibodies are described since 2012 in South
Tyrolean Myotis myotis. This study provide phylogenetic evidence for
either the current or the recent movement of M. myotis from continental
Europe to South Tyrol across the Alpine valleys, which might allow for
the introduction of LYSVs. Serological analyses confirmed antibodies
against EBLV-1 in this bat across the entire region, showing marked
seasonal pattern and a sharp peak of positivity in late summer. No
statistical difference was detected between the maternity colonies
investigated in either the likelihood for infection or the antibody
titres. Indeed, South Tyrolean populations of M. myotis showed no
significant genetic differentiation using nuclear and mitochondrial
markers, supporting the existence of a regional meta-population and a
low philopatric behaviour. This structure, never described for M. myotis
elsewhere, well explains the spread and maintenance of LYSVs trough the
movement of female bats between colonies. Since no virus was detected in
the study, we cannot exclude that our serological data don’t derive from
a cross-reaction with an unknown LYSV. However, because all LYSVs can
cause clinical rabies in humans, this study has a strong impact on
public health regardless of the viral species actually circulating. In
addition, the unravelling of the peculiar genetic structure of South
Tyrolean M. myotis is crucial to inform conservation strategies for this
endangered species.