宁波市2016年麻疹病例特征分析

Characteristic analysis of meases cases in Ningbo,2016

目的了解宁波市2016年麻疹病例的流行病学和基因型特征。方法统计法定传染病报告系统中宁波市麻疹病例相关流行病学资料,Vero/SLAM细胞对麻疹病毒核酸阳性咽试子标本进行病毒分离,采用逆转录-聚合酶反应(RT-PCR)扩增分离株及部分咽拭子标本核蛋白羧基末端450个核苷酸,测序后进行遗传变异分析。结果 2016年宁波市实验室确诊麻疹病例60例,主要集中在4月-5月; 81. 67%(49/60)来源于余姚市;年龄最小患者为3个月,最大为55岁,45例> 20岁,免疫史不详。测序30个序列均为H1a基因型,羧基末端450核苷酸和氨基酸同源性为95. 07%～100%和96. 67%～100%;其中来源于宁波余姚市的24个序列形成一簇,核苷酸和氨基酸同源性为98. 4%～100%和98. 67%～100%;来源于其他县市区6个序列则与历年序列混合分布。来源于余姚市的24个序列第85位氨基酸为天冬酰胺(N),其余序列均为天冬氨酸(D)。结论宁波2016年麻疹病例主要由本土流行株(H1a亚型)引起,引起余姚地区麻疹暴发流行株与历年流行株存在一定差异,可能为一个新的变异株。

Objective To analyze the epiderrfiological and genotype characteristics of measles cases in Ningbo,2016.Methods Statistical epidemiological data of measles cases in Ningbo was collected from infectious disease reporting system,virus isolation was conducted from swab specimens with positive measles virus nucleic acid using Vero/SLAM cells,and reverse transcription-polymerase reaction(RT-PCR)was used to amplify the isolates and the nucleoprotein carboxyl terminal 450 nucleotides in some swab specimens,and the genetic variation analysis was performed after sequencing.Results Totally,60 measles cases were laboratory confirmed in 2016 and mainly concentrated in Apr-May.81.67% cases (49/60)were from Yuyao.The youngest was 3 month and the oldest was 55 years old.45 cases were more than twenty years old and immune history was unknown.The homology of N genes innucleotide (nt)and amino acid (aa)between the 30 Hlα sequences were within 95.07%-100% and 96.67%-100% respectively.24 sequences from Yuyao formed clusters with a respective homology of 98.4%-100% and 98.67%-100%.Other 6 sequences were mixed with sequences over the years.The 85th amino acid in 24 sequences from Yuyao were N and others were D.Conclusion Hla was the predominant epidemic genotype in Ningbo,2016. The strains causing the break in Yuyao were different from strains isolated over the past years in Ningbo,which maybe a new variant of H1α subtype.