Antigenic and genetic divergence of rabies viruses from bat species indigenous to Canada

Antigenic characterisation of over 350 chiropteran rabies viruses of the Am ericas, especially from species reported rabid in Canada, distinguished 13 viral types. In close accord with this classification, nucleotide sequencin g of representative isolates, at both the N and G loci, identified four pri ncipal phylogenetic groups (I-IV), sub-groups of which circulated in partic ular bat species. Amongst the North American bat viruses, there was a notab le division between group I specimens associated with colonial, non-migrato ry bats (Myotis sp. and Eptesicusfuscus) and those of group II harbored by solitary, migratory species (Lasiurus sp. and Lasionycteris noctivagans). C ertain species of Myotis were clearly identified as rabies reservoirs, an o bservation often obscured previously by their frequent infection by viral V ariants of other chiroptera. An additional group (III) apparently circulate s in E. fuscus, whilst viruses harbored by both insectivorous and haematoph agus bats of Latin America clustered to a separate clade (group IV). Compar ison of the predicted N and G proteins of these viruses with those of strai ns of terrestrial mammals indicated a similarity in structural organisation regardless of host species lifestyle. Finally, these sequences permitted e xamination of the evolutionary relationship of American bat rabies viruses within the Lyssavirus genus. (C) 2001 Published by Elsevier Science B.V. Al l rights reserved.