2007-2018年云南省急性弛缓性麻痹病例肠道病毒A71型基因特征

Genetic characteristics of enterovirus A71 isolated from acute flaccid paralysis cases in Yunnan province,2007-2018

目的分析云南省急性弛缓性麻痹(Acute flaccid paralysis,AFP)病例肠道病毒A71型(Enterovirus A71,EVA71)的基因特征。方法收集云南省2007-2018年AFP病例EV-A71阳性分离株,对分离株进行VP1编码区逆转录-聚合酶链反应扩增和核苷酸序列测定,分析核苷酸同源性和基因亲缘关系。结果从2007-2018年云南省AFP病例中分离获得46株EV-A71,与A、B、C基因型代表株和云南省既往其他来源的分离株之间的核苷酸同源性分别为80.6%-83.0%、81.4%-85.4%、85.4%-99.1%、81.7%-99.8%;同年份分离株之间的核苷酸差异在2018年3株的0.63%至2014年9株的3.75%之间,不同年份分离株之间的核苷酸平均差异在1.77%-7.81%之间;基因亲缘进化分析显示,分离株与C4a基因亚型代表株处于同一分支。结论云南省2007-2018年AFP病例的EV-A71分离株均为C4a基因亚型,与本省其他来源EV-A71分离株的基因亲缘关系相近。

Objective To describe genetic characteristics of enterovirus A71(EV-A71)strains isolated from acute flaccid paralysis(AFP)cases in Yunnan province.Methods We obtained virus isolates from EV-A71-positive AFP cases during 2007-2018 in Yunnan.We amplified VP1 coding regions of EV-A71 using reverse transcription PCR,conducted a nucleotide sequence analysis,and determined nucleotide homologies and phylogenetic lineages.Results Forty-six EV-A71 strains were isolated from AFP cases during 2007-2018 in Yunnan,with nucleotide homologies of 80.6%-83.0%,81.4%-85.4%,85.4%-99.1%,and 81.7%-99.8%compared with reference strains of A,B and C genotypes and previous Yunnan strains from other sources.Nucleotide differences among isolates from the same year ranged from 0.63%in 3 strains in 2018 to 3.75%in 9 strains in 2014;among isolates from different years,differences ranged from 1.77%to 7.81%.Phylogenetic analysis showed that the 46 isolates were located in the C4 a subgenotype lineage.Conclusion EV-A71 strains isolated from AFP cases during 2007-2018 in Yunnan belonged to C4 a subgenotype and had a close genetic relationship with local EV-A71 strains from other sources.