Phylogenetic analysis on measles viruses in Zhuhai outbreak during 2017

Objective To analyze the genome of the measles virus strains isolated in Zhuhai city Guangdong Province and to explore the possible viral origin. Methods The fragmentated genome was amplified and sequenced. The sequencing results were assembled into a complete viral genomic sequence by terminal overlapped method. The viral genomic sequence were submitted to the GenBank. The phylogenetic trees were constructed by compared the genomic sequence with sequences presently available on GenBank. The possible sources and the spreading routes of the virus were conjectured accompanied with epidemiological investigation. The amino acid sequence of the virus was inferred according to the sequence and the significance of the mutation was analyzed based on the vaccine strain - Shanghai191. Results The whole genomic sequence of MVs/Zhuhai.CHN/10.17/2[H1] (Accession No: MG972194) was 15 894bp in length and coded six structural proteins and two non-structural proteins. The phylogenetic analysis demonstrated that it was the nearest to KJ755987.1 (99% identity, 15 783/15 894). The consistency of the amino acide sequences of N, P, V, C, M, F, H and L proteins of MG972194 with vaccine strain - Shanghai191 were 96.6% (507/525), 98.2% (498/507), 97.7% (292/299), 96.8% (180/186), 99.1% (332/335), 96.6% (534/553), 98.5% (608/617) and 99.3% (2 168/2 183), respectively. Conclusions The epidemiological evidences supported that measles virus type H1 strains causing local outbreaks in Zhuhai during 2017 were likely to be originated from patients of Zhejiang province. The amino acide mutation within N, P, L and V proteins seemed to modify capabilities of MG972194 in genome duplication and transcription, pathopoiesia, inducing host T cell immunity and balance between the cellular and humoral immunity. Key words: Measles virus; Genome; Sequencing; Mutation; Phylogenetic analysis