Evolutionary analysis of rabies virus isolates from Guangxi Province of southern China

Xian-Kai Wei,Ting Rong Luo,Xiao-Xia He,Yan Pan,Xiao-Ning Li,Cheng Liu,Jing-Jing Liang,Hai-Bo Tang,Yi-Zhi Zhong

doi:10.1186/s12917-018-1514-0

Abstract

BackgroundRabies is a severe epidemic in Guangxi province, China, with hundreds of deaths occurring each year. In the past six decades, rabies has emerged three times in Guangxi, and the province has reported the largest number of rabies cases in China. The domestic dog is the principal vector for rabies, and 95% of human cases are associated with transmission from dogs.ResultsTo understand the genetic relationship between street rabies virus (RABV) from Guangxi, genetic diversity analysis was performed using RABV isolates collected between 1999 and 2012. The N gene of 42 RABV isolates, and the P and M genes, as well as fragments of the 3′ terminus (L1–680) and the polymerase activity module of the L gene (Lpam) of 36 RABV isolates were sequenced. In addition, whole genome sequencing was performed for 5 RABV isolates. There was evidence of topological discrepancy in the phylogenetic trees based on different genes of the RABV isolates. Amino acid variation of the deduced N protein exhibited different patterns to those obtained from the P and M proteins reported here, and the previously reported G protein (Tang H. et al., PLoS Negl Trop Dis, 8(10): e3114, 2014), and L1–680 and Lpam. These RABV isolates were divided into three main branches against fixed strains.ConclusionRABV is prevalent in Guangxi province and strains collected over the last two decades belong mainly to three groups (I, II, III). These RABV isolates reveal genetic diversity. Individual RABV genes from Guangxi exhibit different evolutionary characteristics. The results will have benefits for continuing comprehensive rabies surveillance, prevention and control in China.

Highlights

Rabies is a severe epidemic in Guangxi province, China, with hundreds of deaths occurring each year
Previous research on the phylogenetic analysis of the rabies virus (RABV) N gene has identified differences in RABVs found in bats, compared to those found in terrestrial mammals [1, 2]
Phylogenetic analysis based on the 3′ terminus of the N gene shows that RABV isolates from Guangxi province, south China can be divided into four groups [15]

Summary

Introduction

Rabies is a severe epidemic in Guangxi province, China, with hundreds of deaths occurring each year. In the past six decades, rabies has emerged three times in Guangxi, and the province has reported the largest number of rabies cases in China. Two distinct clades of RABV isolates found in China were identified by genetic analysis [10, 11]. Evolutionary dynamic analysis based on the G gene shows that the RABV currently circulating in China consists of three main groups [13], and that the RABV in China and Southeast Asia share a common ancestor [14]. Phylogenetic analysis based on the 3′ terminus of the N gene shows that RABV isolates from Guangxi province, south China can be divided into four groups [15]. Further studies have demonstrated that isolates from groups I, II, and III are lethal once introduced in mice, whereas isolates of group IV are not fatal to either adult or suckling mice [15]

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