Molecular characterization of rabies virus isolates from Mexico: Implications for transmission dynamics and human risk

Twenty-eight samples from humans and domestic and wild animals collected in Mexico between 1990 and 1995 were characterized by using anti-nucleoprotei n monoclonal antibodies and limited sequence analysis of the nucleoprotein gene. The variants of rabies viruses identified in these samples were compa red with other isolates from Mexico and the rest of the Americas to establi sh epidemiologic links between cases and outbreaks and to increase the unde rstanding of rabies epidemiology in the Western Hemisphere. Antigenic and g enetic diversity was found in all samples from dogs and dog-related cases, suggesting a long-term endemic situation with multiple, independent cycles of virus transmission. Two isolates from bobcats were antigenically and gen etically homologous to the rabies variant circulating in the Arizona gray f ox population, indicating a wider distribution of this variant than previou sly reported. Rabies isolates from skunks were unrelated to any variant ana lyzed in this study and represent a previously unrecognized cycle of rabies transmission in skunks in Baja California Sur. Two antigenic and genetic v ariants cocirculating in southern and eastern Mexico were found in viruses obtained from cases epidemiologically related to vampire bats. These result s serve as a baseline for the better understanding of the molecular epidemi ology of rabies in Mexico.