[Genetic characteristics of varicella zoster virus in Shandong province from 2020 to 2021].

Objective: To investigate the genetic characteristics of varicella zoster virus (VZV) in Shandong province from 2020 to 2021. Methods: From April 2020 to December 2021, 85 herpes fluid samples from suspected varicella patients in Shandong province were collected. The qPCR was used to detect viral DNA and screen suspected samples. Six single nucleotide polymorphisms (SNPs) of ORF22 fragment and ORF38 fragment in positive samples were examined via PCR and Sanger sequencing to identify the viral genotypes. Four SNPs of ORF38 and ORF62 were examined to identify the vaccine and wild-type strains. The sequences were analyzed with Sequencher and MEGA7 software, using the VZV reference strain sequences from GenBank. Results: In the 85 samples suspected of varicella, 80 were VZV positive and wild-type strains belonging to Clade 2. Compared with clade 2 representative strains, the nucleotide and amino acid similarities of ORF22 fragment were 99.5%-100% and 98.5%-100%, respectively. SD20-1, SD20-5, SD20-6, SD20-8, SD20-9, SD20-10, SD20-11, SD20-12, SD20-13, SD20-30 and SD20-31 had a A➝G nucleotide mutation at 37990, causing amino acid change from glutamine to arginine. SD21-1 had a C➝A nucleotide mutation at 38059, causing threonine to asparagine during coding. Conclusions: From 2020 to 2021, all VZV strains in Shandong province are the wild-type strains belonging to Clade 2.