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@#Objective To analyze the etiology of clinical cases of live attenuated varicella vaccine.Methods 64 samples of varicella vesicle fluid from 49 patients clinically diagnosed as varicella cases in phase Ⅲ clinical trial of live attenuated varicella vaccine in enterprises(the test site was Henan Province) were collected,extracted for DNA,and distinguished for wild-type strains and vaccine strains by PCR and restriction fragment length polymorphism(PCR-RFLP).Genotype was analyzed using the genotyping method recommended at the international(varicella-zoster virus,VZV) nomenclature meeting2008.Results 64 vesicle fluids were all wild-type strains(Pst Ⅰ~+Sma Ⅰ~-BssH Ⅱ~-Nae Ⅰ~-),and no vaccine-related cases occurred.All 49 isolates belonged to Clade 2.Additionally,compared with Clade 2,a synonymous mutation(T→C) in SNP18 082 was detected in all 49 isolates,and a mutation(C→A) in SNP790 was detected in one isolate.Conclusion In the clinical trial of live attenuated varicella vaccine in Henan Province,all the clinical cases were caused by infection of wild-type strain which belonged to Clade 2 genetic branch.
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Objective@#To clarify the genotype of varicella-zoster virus (VZV) in Jilin province in 2017, and to discriminate between vaccine strain and wild-type strain.@*Methods@#Vesicle fluid and throat swab samples were collected from 10 individuals with suspected VZV in Jilin province from January to March of 2017. Real-time fluorescent quantitative PCR was used to detect viral nucleic acid. Specific regions of ORF22, ORF38 and ORF62 of VZV were amplified by PCR. Viral genotype was determined by five SNPs of ORF 22 and vaccine strain or wild-type strain was distinguished by four SNPs of ORF 38 and ORF 62. The results were analyzed with MEGA5 and BioEdit software, using the VZV reference strain sequences from GenBank.@*Results@#VZV-positive strains were detected in 10 samples, all belonged to Clade 2. There was a synonymous mutation (C→T) in position 38 048 of JL17-7 strain. The nucleotide homology of ORF22 showed that all 10 samples were on the same branch with the Clade 2 referenced strains. Compared with Clade 2 referenced strains, the homology of nucleotide and amino acid for all 10 samples were 99.5%-100% and 99.3%-100%, respectively. The four specific SNPs of ORF38 and ORF62 in 10 samples were A-T-T-T, which were consistent with wild-type strain.@*Conclusions@#This study reveals that the VZV strains circulating in Jilin province in 2017 were all wild-type strains belonging to Clade 2.
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Rotaviruses are important enteric pathogens for humans and animals. Group A rotaviruses (RV-A) are the most common agents of severe gastroenteritis in infants and young children and vaccination is the most effective method to reduce RV-A-associated diseases. G1P[8], the most prevalent RV-A genotype worldwide, is included in the RV-A vaccine Rotarix®. The discrimination between wild-type G1P[8] and vaccine G1P[8] strains is an important topic in the study of RV-A epidemiology to manage outbreaks and to define control measures for vaccinated children. In this study, we developed a novel method to segregate the wild-type and vaccine strains using restriction endonucleases. The dsRNA from the Rotarix® vaccine was sequenced and the NSP3 gene was selected as the target gene. The vaccine strain has a restriction pattern that is different than that of wild-type RV-A G1P[8] isolates after digestion with the restriction endonuclease BspHI. This pattern could be used as a marker for the differentiation of wild-type G1P[8] strains from the vaccine strain.