Molecular epidemiologic characteristics of human rabies virus in the North and Center provinces of Vietnam, 2020 - 2022

Abstract

This study aims to describe molecular epidemiologic characteristics of human rabies virus in the North and Center provinces of Vietnam, 2020 - 2022. During 2020 and 2022, a total of 164 samples collected from 83 suspected human rabies in some Northern and Center provinces of Vietnam were tested for rabies by RT - PCR. 28/83 cases were confirmed rabies positive. Rabies - positive cases were scattered through the years and found in 19/28 provinces. The full gene of nucleoprotein (N) of 15 positive rabies samples was successfully sequenced and analyzed phylogenetically using the maximum - likelihood method. The results showed that 15 rabies viruses in the study were phylogenetically closely related to RABVs that caused rabies outbreaks in dogs in Northern Vietnam in the previous years with high nucleotide similarity (95.1% - 100%). In comparison with the rabies virus isolates
worldwide, 15 rabies virus sequences all belonged to the Lyssavirus genotype I and were in China I clade, in which, some viruses shared very high nucleotide similarities (99% - 100%) with rabies viruses isolated in dogs in China. Our results provide virological evidence that domestic dogs are the main source of rabies infection in humans in Vietnam and suggest that the possibility of cross-infections of the rabies virus has occurred between China - Vietnam border.