[Imported B3 genotype measles viruses were isolated from measles cases in the Chinese mainland]

We isolated and identified the genotypes and molecular characteristics of the imported B3 measles virus (MeV) in the Chinese mainland. The Vero/SLAM cell line was used to isolate the viruses. Reverse transcription-polymerase chain reaction was undertaken to amplify the 450 nucleotide acids of the 3-terminal of the nucleoprotein gene. A phylogenetic tree was constructed and similarities in homology assessed. Results suggested that the Shanghai isolates MVi/Shanghai. CHN/38. 13/02 [B3] and MVi/Shanghai. CHN/40. 13/02[B3] were clustered within the same genotype group as the World Health Organization (WHO) B3 genotype reference strain. The number of differences in nucleotide acids between the two Shanghai isolates was one. The homology of nucleotide acids between the Shanghai isolates and the WHO B3 genotype reference strain (MVi/Ibadan. NGA/0.97/1/B3) was 98%. Comparative results from the Measles Nucleotide Surveillance system suggested that the sequences of Shanghai isolates and the 2013 vi- ruses from Australia, Japan, Korea, Hong Kong China, Philippines and Iran were identical. This is the first time that the B3 genotype of MeV in the Chinese mainland has been isolated since 1993. These data can be used to create a "baseline" of genetic information for measles viruses in China, and help to trace the transmission of measles viruses in China and the rest of the world.