Genetic characterization of contemporary wild-type measles viruses from Vietnam and the People's Republic of China: identification of two genotypes within clade H

Genetic characterization was conducted on 17 wild-type measles viruses isol ated near Hanoi, Vietnam, during 1998 as well as on eight viruses isolated in the Hunan, Hainan, Shandong, and Anhui provinces of the People's Republi c of China during 1995, 1998, and 1999. Previous studies had shown that, co mpared to wild-type measles viruses found in other parts of the world, wild -type viruses from China were genetically distinct and comprised a new clad e of viruses, clade H. In this study, sequence analyses of the nucleotides coding for the COOH terminal 150 amino acids of the nucleoprotein (N) and t he entire hemagglutinin (H) protein indicated that although all of the viru ses from Vietnam were members of clade H, they were clearly distinct from t he Chinese viruses. With the exception of MVi/Beijing. China /94/1, the Vie tnamese viruses differed from all of the Chinese viruses by at least 3.5 an d 2.5% at the nucleotide level for the N and H genes, respectively. These d ata suggest that clade H should be divided into two genotypes with the Chin ese viruses placed in genotype HI and the Vietnamese viruses in genotype H2 . Sequence analysis of measles viruses imported into the United States from either China or Vietnam demonstrated that this designation of genotypes wi ll be helpful in future measles surveillance activities. (C) 2001 Elsevier Science B.V. All rights reserved.