Identification of regional variants of the rabies virus within the Canadian province of Ontario

Abstract

Although rabies outbreaks in most parts of the world tend to be host species-specific the rabies currently enzootic in the Canadian province of Ontario is hosted by two wildlife species, the red fox and the striped skunk. Previous studies employing monoclonal antibody panels failed to identify any host-specific differences in Ontario rabies virus street isolates, but certain observations suggested the existence of more than one viral strain in terrestrial mammals of this region. The extent of variation of the rabies virus circulating within this region has been re-examined using molecular biology techniques. The N gene of several independent isolates was amplified using PCR and the resulting products were compared by restriction enzyme analysis and, in some cases, by DNA sequencing. This analysis confirmed that there was indeed no host-specific variation in the portion of the viral genome under study but there were, however, very clear and consistent differences in the virus from distinct geographical regions.