[Genetic analysis of a genotype F mumps virus based on its complete genome sequence]

Mumps virus strains of genotype F have been circulating in China for decades. To identify genetic variation of mumps virus based on the complete genome sequence of a mumps isolate of genotype F, the complete genome of the genotype F reference strain, MuVi/Shandong. CHN/4.05 [F] was sequenced. Genetic characteristics of this virus were analyzed and compared with the complete genome sequences of others genotypes available in GenBank. The genetic differences in antigenic sites were also compared between the genotype F strain and the vaccine strains. The nucleotide differences between MuVi/Shandong. CHN/4.05 [F] and other genotypes of mumps virus based on the whole genome ranged between 3.8% and 6.5%. The maximum and minimum difference was found between MuVi/Shandong. CHN/4.05 [F] and genotype A (the vaccine strains), and genotype B-N strains, respectively. There were 26 N-glycosylation sites in the strain MuVi/Shandong. CHN/4.05 [F] and all other genotypes of mumps virus, however, one N-glycosylation site was absent from the vaccine strains, which was at the aa position 464-466 of the HN gene. Variation was detected at some of the known antigenic sites of mumps virus strain MuVi/Shandong. CHN/4.05 [F] and the vaccine strains. Genetic variations were detected in the epidemic mumps virus strain in China as well as in other genotypes of mumps virus strains and the vaccine strains across the complete genome. These results indicate the need to further strengthen the surveillance of genetic variation of wild type mumps virus.