Epizootic situation and molecular genetic characteristics of the rabies virus isolated from the brain of domestic reindeer in Yakutia

Abstract

Rabies was registered among horses, domestic reindeer and dogs on the territory of the Republic of Sakha (Yakutia) in 2001– 2021. Rabies virus (Rabies lyssavirus) was detected in biomaterial from wild animals in Arctic foxes, red foxes, wolves, colts, ermine and sables. In the Arctic zone of Yakutia in 2023, rabies virus was isolated from a brain sample from one of the domestic reindeer of a herd showing clinical signs of severe agitation and aggression to humans. It is assumed that the reindeer was infected with rabies virus when bitten by a rabies-sick Arctic fox, as the range of distribution of these animals in the region is quite large. Rabies virus detection studies were conducted using polymerase chain reaction, enzyme immunoassay and fluorescent antibody method. The diagnosis of rabies was confirmed in all diagnostic tests. The nucleic acid fragments were isolated from the positive samples by the PCR method and their nucleotide sequences were determined. Analysis of the nucleotide sequences of the viral genome revealed phylogenetic relatedness of the isolated rabies virus isolate in the Arctic zone of Yakutia with the rabies viruses circulating in some areas of the North American continent, including Greenland (two isolates), Canada (six), and the United States (three). The isolate of the rabies virus from the brain of domestic reindeer in the Arctic zone of Yakutia belongs to the group of strains of American origin (USA1) and is phylogenetically close to the strains isolated in Greenland, Canada, and the USA. The studied virus isolate territorially corresponds to the known antigenic variant 3, established earlier in the north of the Asian part of Russia, in particular in Yakutia.