Nationwide distribution of varicella-zoster virus clades in China

Songtao Xu,Qiuhua Wu,Haiyan Wang,Mao Naiying,Meng Chen,Huanying Zheng,Daxing Feng,Wang Shuang,Mukai Chen,Pengbo Yu,Chaofeng Ma,Zhang Yan,Wenbo Xu,Chongshan Li,Xiaoguang Xu,Mengyuan Qi,Ai‐Li Cui ,Zhendong Zhu ,Jian Zhou ,Jun He

doi:10.1186/s12879-016-1863-x

Abstract

BackgroundIn 2010, a universal nomenclature for varicella-zoster virus (VZV) clades was established, which is very useful in the monitoring of viral evolution, recombination, spread and genetic diversity. Currently, information about VZV clades has been disclosed worldwide, however, there are limited data regarding the characterization of circulating VZV clades in China, even where varicella remains widely epidemic.MethodsFrom 2008 to 2012, clinical samples with varicella or zoster were collected in General Hospital in eight provinces and analyzed by PCR, restriction endonuclease digestion and sequencing. The viral clades were determined by analysis of five single nucleotide polymorphisms (SNPs) within the 447-bp fragment of open reading frame (ORF) 22, and the restriction fragment length polymorphisms (RFLPs) of ORF 38 (PstI), ORF 54 (BglI) and ORF 62 (SmaI) were evaluated to understand genetic diversity of VZV and determinate varicella vaccine adverse event (VVAE).ResultsSeventy-seven varicella and 11 zoster samples were identified as being positive for VZV. The five SNPs profile showed that the majority of VZV strains belonged to clade 2, but clade 5 and clade 4 strains were also found in Guangdong. The RFLPs analysis of the DNA fragments of ORF 38, 54 and 62 showed that 85 of these samples were characterized as PstI + BglI + SamI-, and the remaining three VZV strains from varicella patients were characterized as PstI-BglI + SamI+ which is the genetic profile of VVAEs.ConclusionsThe study suggested that the predominant clade 2 VZVs had been continually circulating since at least the 1950s in China. Nearly all VZV strains except VVAEs possessed the genetic profile of PstI + BglI + Sam-. However, the other clades were also found to be co-circulating with clade 2, especially in the border regions. These results highlighted the need for the constant and broad use of virologic surveillance to provide an important genetic baseline for varicella control and vaccination programs in China.

Highlights

In 2010, a universal nomenclature for varicella-zoster virus (VZV) clades was established, which is very useful in the monitoring of viral evolution, recombination, spread and genetic diversity
This study describes the clade distribution and genetic profile of circulating VZV strains throughout China, and distinguishes vaccine strains from wild-type strains
Only one clade VII strain was exclusively isolated in the United States (US) in 2002 [21]; in Asia, VZV clade 2 has been the dominant clade according to previous publications from Korea, Japan, and China; clade 2 strains were not found circulating in India, Nepal and Bangladesh, where clade 4 and 5 strains were dominant [2, 22,23,24]

Summary

Introduction

In 2010, a universal nomenclature for varicella-zoster virus (VZV) clades was established, which is very useful in the monitoring of viral evolution, recombination, spread and genetic diversity. Genotyping of VZV contributes to reveal viral diversity, recombination, evolution patterns and transmission pathways. To achieve these goals, several groups have published different schemes by using molecular techniques such as the sequencing, restriction fragment length polymorphisms (RFLPs) and single nucleotide polymorphisms (SNPs) since the 1990s, the different nomenclature methods will not facilitate interchange of information [2,3,4,5,6,7]. The new universal nomenclature will be useful for the interchange and comparison of genotyping data worldwide [6, 8, 9]

Methods

Results

Discussion

Conclusion