Genotyping of wild-type strains of varicella-zoster virus and their differentiation from Oka vaccine strain
Objective To analyze the genotype of varicella-zoster virus (VZV) strains isolated from patients with chickenpox or zoster and to differentiate them from Oka vaccine strain by molecular analysis. Methods In the present study, single nucleotide polymorphisms(SNP) based VZV genotypes were analyzed in 19 VZV isolates using the polymerase chain reaction and restriction fragment length polymorphisms analysis of DNA fragments of the open reading frames 38, 54, 62, and the 1t5 repeat region. Results The genotypes of 19 VZV isolates including two different groups with 52.7% of Pst Ⅰ+ Bgl Ⅰ+ R5A and 47.3% of Pst Ⅰ+ Bgl Ⅰ+ R5B, which is very different from those found in North America, Europe and Japan. All the Chinese isolates are wild-type strains with ORF62 Sma Ⅰ-. No Oka vaccine strains were revealed among the isolates. Conclusion Chinese VZV strains reported in this study showed different molecular characteristics from those circulating in Europe, North America and Japan. The SNPs in ORF62 and ORF38 may be used to distinguish VZV wild-type strains and vaccine strain in clinical isolates in China. 
 
Key words: 
Varicella-zoster virus;  Genotyping;  Oka strains;  Wild-type strains