ABSTRACT
Objective@#To analyze the genetic characteristics of rubella virus isolated from 2012 to 2015 in Guizhou province.@*Methods@#A total of 390 cases of suspected measles were collected from Guizhou measles network laboratory from 2012 to 2015 and 25 cases of rubella cases were diagnosed. Rubella virus isolation was performed using Vero/SLAM cells. The presence of rubella viral RNA was detected using Real-time RT-PCR after RNA extraction from infected tissue culture cells. Fragments of 480 bp and 633 bp nucleotides of E1 genes of the isolates were amplified by RT-PCR and the PCR products were sequenced and spliced. The phylogenetic tree was conducted based on the 739 bp nucleotide sequences of E1 genes and gene characteristic analysis was performed.@*Results@#There were 19 cases of rubella outbreaks and 6 cases of rubella sporadic cases in 25 cases of suspected rubella cases. There were 11 males (44.0%) and 14 females (56.0%). The mean age and standard deviation were (12.3±3.9) years. A total of 10 rubella strains were isolated. The results of phylogenetic analysis showed that 7 strains of rubella virus isolates belonged to genotype 1E and the other belonged to genotype 2B. The nucleotide acid and amino acid homology among 7 strains 1E genotype were 99.0%-100% and 100% respectively. 2B genotype of 3 strains of nucleotide and amino acid homology were 99.4%-100% and 99.5%-100% respectively. Ten strains of rubella virus were not mutated in the E1 glycoprotein gene, Asn 177 and Asn 209 N-type glycosylation sites and E1 antigen epitopes between 213 and 285aa.Among them, 7 strains of 1E genotype had a mutation from leucine to phenylalanine in 338 amino acid, 2 strains of 2B genotype at 377 amino acids from valine to alanine.@*Conclusion@#Rubella virus epidemic was caused by 1E and 2B genotypes in Guizhou from 2012 to 2015.Ten strains of rubella virus were highly conserved in nucleotide and amino acid sequences and there was no variation of important functional sites.
ABSTRACT
Objective To analyze the genetic characteristics of measles virus strains causing two outbreaks in Guizhou province from November 2014 to March 2015. Methods Throat swab samples collect-ed from measles cases in two outbreaks were inoculated into Vero/SLAM cells. Viral RNAs were extracted from positive cultures. Nucleoprotein genes were amplified by using reverse transcription-polymerase chain reaction ( RT-PCR) and the PCR products were sequenced and analyzed. Results Eleven strains of wild-type measles virus were isolated from the two measles outbreaks and all of them belonged to H1a sub-geno-type. Phylogenetic analysis showed that those strains were clustered into two distinct branches. Differences in nucleotide and amino acid genetic distances between the 11 strains of measles virus and the WHO reference strain of H1a sub-genotype (Chin9322) were 1. 1%-1. 6% and 0. 7%-3. 4%, respectively. Compared with the reference strain Chin9322 and Guizhou epidemic strains in recent years, six strains showed amino acid sequence mutations in 47 ( G to S) , 82 ( S to G) and 122 ( R to K) sites and two strains had a mutation in 98 ( P-L) site. Conclusion H1a sub-genotype measles virus was the predominant pathogen causing two measles outbreaks in Guizhou province during 2014 to 2015. Moreover, it was also a predominant sub-geno-type circulating in China and Guizhou province. Different measles virus strains of H1a sub-genotype contin-ued to be prevalent in Guizhou province. This study provided some scientific data for the control and elimina-tion of measles in Guizhou province.
ABSTRACT
Objective To identify the rubella virus circulated in Guizhou province in 2012 ,and confirm the genotype and analyze the genetic characterization of rubella virus isolated .Methods The throat swab samples were collected from suspected rubella cases during the rubella outbreak and sporadic in 2012 .Rubella virus isolation was performed using Vero/SLAM cells .The presence of vi-ral RNA was detected using real-time RT-PCR after RNA extraction from infected tissue culture cells .Fragments of 944 nucleotides of E1 genes of the isolates were amplified by RT-PCR ,the PCR products were directly sequenced and analyzed .The phylogenetic trees based on the 739 nucleotide sequences 1E was conducted with the rubella viruses isolated in Guizhou province in 2012 and 32 WHO reference sequences representing 13 genotypes .Results 5 rubella virus strains were isolated in Guizhou province for the first time .The results of phylogenetic analysis showed that all 5 rubella virus isolates belong to genotype 1E .The nucleotide acid and a-mino acid homology among 5 rubella virus isolates were 99 .8% -100 .0% and 100 .0% respectively .Compared with the WHO ref-erence strain (Chinese strain T14-CH-02) ,the nucleotide acid and amino acid homology were 98 .7% -98 .9% and 100 .0% respec-tively ;while compared with another WHO reference strain (Malaysia strains M1-MAL-01) ,the nucleotide acid and amino acid ho-mology were 97 .5% -97 .6% and 99 .5% .Conclusion Genotype 1E rubella virus was the predominant genotype in Guizhou prov-ince in 2012 ,which was similar to the other provinces .This study accumulated the molecular epidemiological baseline date in Guizhou province .