A Molecular Epidemiological Study Of Rubella Virus Isolates From 2011 To 2017 In Shanghai

Objective: To analyze the molecular epidemiological characteristics of rubella v irus wild strains isolated in Shanghai during 2011-2017.Methods: Throat swabs were collected from suspected measles or rubella patients found by measles and rubella surveillance in Shanghai during 2011-2017,which conformed to the definition of the cases stipulated in the Shanghai Measles and Rubella Surveillance Scheme.Samples were used to conduct real-time PCR of measles and rubella,which measles negative and rubella positive continue to cell culture for rubella virus.After identification with RT-PCR,the gene of E1 in rubella virus was amplified and sequenced,followed by molecular epidemiological analysis.Results: Totally 417 strains of rubella virus were isolated during 2011-2017.Compared 393 isolates with the WHO reference strains of all genotypes,phylogenetic tree was constructed based on the amplified 739 nucleotides sequences.These isolates were characterized as two genotypes respectively,124 strains were defined as genotype 1E which were closer to the WHO reference strain from China(RVi/Shandong.CHN/0.02/),and others were genotype 2B while 5 strains of them were defined as a lineage.Most of the nucleotide mutations were nonsense mutation,and the amino acid sequences were highly conserved.All the genotype 1E rubella viruses except one strain occurred the same mutation at aa338 site.Conclusion: Two genotypes of rubella virus circulated in Shanghai during2011-2017.Genotype 1E appeared to be the predominant genotype during 2011-2013,genotype 2B was continuous exiting since being found in 2011 and appeared to be the predominant genotype during 2014-2016.