Abstract：Objective: The purpose of this study is to genetically identify and characterize the wild type measles virus that responsible for the family measles outbreak at Zhongshan city, in April, 2014. Methods: Pharyngeal swabs from 3 patients of acute phase were collected. The nucleocapsid (N) gene (450 bp) was measured by RT-PCR and sequenced. The genotype and molecular characteristics of the nucleocapsid fragment was then analyzed and compared with both WHO reference strain(Human,CH/93/7-AF045212) and Shanghai 191 strain. Phylogenetic distance between the measles virus in this study and the reference strains were evaluated by generating the phylogenetic tree using the neighbor-joining method. Results: Nucleocapsid sequences of the 3 patients had 100% similarity and phylogenetically associated with H1 type. When comparing the nucleocapsid virus in this study with the WHO reference strain and Shanghai 191 strain, 97% and 92% nucleotide similarities, and 95% and 88% amino acid similarities were found, respectively. In addition, 6 amino acids mutation were found including 1 serine substitution by alanine at the 84th locus, causing protein polarity change. Conclusion: 3 nucleocapsid virus samples in this study had the same phylogenetic origin and associated with H1 type. Mutations of amino acid at new sites were identified which highlighted the needs for further attention.
2016, Vol. 23 
