Molecular epidemiological analysis of measles virus in Beijing from 2015 to 2019 / 中华微生物学和免疫学杂志

Objective:To analyze the molecular epidemiological characteristics of measles virus (MV) in Beijing from 2015 to 2019, and to provide laboratory basis for measles elimination.Methods:Measles virus-positive throat swab samples were collected through the Beijing Measles Laboratory network from 2015 to 2019. After the viral nucleic acid was extracted, 450 nucleotide fragments of the C terminal of the N gene of MV were amplified by RT-PCR. Nucleotide sequencing was performed for the amplified products. The phylogenetic tree was constructed with the representative strains of WHO measles virus genotype D8 genotype reference strains in China and other countries. Genotype identification was conducted and the nucleotide and amino acid homology analysis was carried out. A descriptive analysis of measles cases with D8 and B3 genotypes was conducted.Results:From 2015 to 2019, the genotypes of 546 MV were identified in the city, including 531 of H1a genotype, five vaccine strains, one of B3 genotype, and nine of D8 genotype, among which eight were epidemic strains in 2019. The homology of indigenous H1a genotype MV nucleotide and amino acid was 91.5%-100.0% and 73.6%-100.0%.In 2019, all eight cases of D8 genotype measles were adults, with two being an outbreak and the remaining six sporadic cases.Conclusions:The imported D8 genotype had become the main MV genotype in Beijing in 2019. With the decrease of measles incidence in 2019, native genotype H1a was no longer dominant, while other different genotypes were imported, forming a mixed epidemic trend. It was suggested that in the elimination of measles in Beijing, efforts should be made not only to block the transmission of local measles virus, but also to prevent and control the import and continuous transmission of non-local genotype virus, so as to avoid the risk of establishing local transmission by gradually evolving into a dominant strain.

The first outbreak of measles virus caused by imported genotype D8 in Jiangsu province of China

ABSTRACT Here we reported the outbreak of measles cases caused by the genotype D8 measles virus for the first time in Jiangsu province in China, which was possibly imported by a foreign student from Laos. Throat swab specimens were collected, and used to isolate virus. 634-bp fragment of the N gene and 1854-bp fragment of H gene were amplified by reverse transcription-PCR and sequenced, respectively. Phylogenetic results indicated that they belonged to genotype D8 measles virus. Further epidemiology investigation showed that the adults with D8 measles virus infection did not receive measles vaccine before having measles. In China, almost all D8 genotype MeV only infected those population without receiving measles vaccine immunization. Therefore, it is still necessary to implement the supplement activity of measles immunization target adult with immunity gap.

Isolation and identification of the first D8 genotype measles virus in Liaoning province / 中华实验和临床病毒学杂志

Objective@#To analyze the gene characterization on the first imported D8 genotype measles virus in Liaoning province.@*Methods@#In this study, Vero/Slam cells were used to isolate measles viruses from throat swabs. Fragments of the H gene (1854 nucleotides) and N gene (450 nucleotides) were amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the PCR products were sequenced and analyzed.@*Results@#The measles virus isolates and World Health Organization (WHO) D8 genotype reference strain (MVi/Manchester.GBR/30.94) belonged to the same branch in the genetic relationship tree. The nucleotide homology of the N and H gene was 98.9%. Phylogenetic trees were constructed with reference strains of the genotype D8 measles virus of China downloaded from GenBank. The result showed that the nucleotide similarities between the measles virus isolated in this study and the D8 genotype measles virus prevalent in Hong Kong from 2012 to 2016 and MVi/LosPatios.COL/11.18/D8 in Columbia was 100%.@*Conclusions@#It is the first time to do surveillance for the D8 genotype measles virus since measles virus surveillance was carried out. It was of great significance to accumulate the bases of measles virus molecular epidemiology in Liaoning province, and helpful to analyze and trace the transmission of measles virus in the whole country and the world.

Molecular epidemiology of measles virus infection in Shanghai in 2000–2012: the first appearance of genotype D8

Purpose: The purpose of this study was to identify measles virus in Shanghai in 2012 and study the genotype trend of measles virus epidemic strains during 2000–2012. Methods: Nose and throat swab specimens were collected from 34 suspected measles cases in Shanghai. Measles virus was isolated using Vero-SLAM cells (African green monkey kidney cells/lymphoid signal activating factor-transfected African green monkey kidney cells). The 450 bp of C terminus of the N gene and the entire hemagglutinin gene sequence was amplified using RT-PCR. Phylogenetic analysis was performed by comparing the seven measles strains in Shanghai with the reference strains for H1a, H1b and D8 genotypes, as well as the Chinese measles virus vaccine strain. Results: Seven measles viruses strains were isolated from the 34 throat swap specimens. Six strains were genotype H1a, which is the predominant strain in China and one strain was genotype D8, which is the first imported strain since 2000. All these seven strains maintained most of the glycosylation sites except subtype H1a, which lost one glycosylation site. Conclusion: Since 2000, measles virus strains in Shanghai are consistent with measles virus from other provinces in China with H1a being the predominant genotype. This study is also the first report of genotype D8 strain in Shanghai. All strains maintained their glycosylation sites except H1a that lost one glycosylation site. These strains could still be neutralized by the Chinese measles vaccine. We suggest that Shanghai Center for Disease Control laboratories should strengthen their approaches to monitor measles cases to prevent further spread of imported strains. .