Nationwide distribution of varicella-zoster virus clades in China

Xu et al. BMC Infectious Diseases Nationwide distribution of varicella-zoster virus clades in China Songtao Xu 0 Mukai Chen 4 Huanying Zheng 3 Haiyan Wang 9 Meng Chen 8 Jianhui Zhou 7 Wang Shuang 7 Pengbo Yu 6 Chaofeng Ma 11 Jilan He 10 Daxing Feng 5 Zhu Zhen 0 Zhang Yan 0 Mao Naiying 0 Aili Cui 0 Qiuhua Wu 0 Mengyuan Qi 1 Chongshan Li 2 Xiaoguang Xu 1 Wenbo Xu 0 0 National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention , Beijing City 102206 , China 1 Department of Neurosurgery, Second Affiliated Hospital of Dalian Medical University , Dalian 116027, Liaoning Province , China 2 Shanghai Center for Disease Control and Prevention , Shanghai City 200336 , China 3 Guangdong Center for Disease Control and Prevention , Guangzhou City 510300, Guangdong Province , China 4 The First Affiliated Hospital of Sun Yat-sen University , Guangzhou City 510080, Guangdong Province , China 5 Henan Center for Disease Control and Prevention , Zhengzhou City 450016, Henan Province , China 6 Shaanxi Center for Disease Control and Prevention , Xian City 710012, Shannxi Province , China 7 Jilin province Center for Disease Control and Prevention , Changchun City 130021, Jilin Province , China 8 Beijing Center for Disease Control and Prevention , Beijing City 100021 , China 9 Shandong Center for Disease Control and Prevention , Jinan City 250014, Shandong Province , China 10 Sichuan Center for Disease Control and Prevention , Chengdu City 610014, Sichuan Province , China 11 Xi'an city Center for Disease Control and Prevention , Xian City 710031, Shannxi Province , China Background: 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. 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. Methods: From 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). Results: Seventy-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. Conclusions: The 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. Varicella-zoster virus; Clade; Varicella vaccine adverse event; Genetic profile; China - Background Varicella-zoster virus (VZV) is highly contagious and causes two diseases. The primary infection results in varicella (chickenpox), which usually occurs early in life. Subsequently, the virus establishes a lifelong latent infection in the sensory nerve ganglia, which reactivates to cause zoster (shingles) under conditions of declining immunity that are most commonly associated age [1]. 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, however, the different nomenclature methods will not facilitate interchange of information [2–7]. In 2010, Breuer et al. summarized the previous nomenclature methods and proposed a novel nomenclature for VZV: clade 1–5 and two putative clades (VI and VII). The new universal nomenclature will be useful for the interchange and comparison of genotyping data worldwide [6, 8, 9]. The universal childhood varicella vaccination program was initiated in the United States (US) in 1995 [10, 11]. Curren (...truncated)