苏州市2004年至2010年麻疹流行特征及其野毒株基因特征

Epidemiology and genetic characteristics of wild strains of measles viruse isolated from cases in Suzhou city during 2004--2010

目的通过对苏州市2004年至2010年麻疹发病情况及流行株的基因型别和特征进行分析，了解麻疹发病情况及流行株基因特点，为加强麻疹病毒学监测，实现消除麻疹提供科学依据。方法收集2004年至2010年苏州市麻疹病例，分析麻疹的流行病学特征，采集2009年至2011年57例麻疹患者咽拭子和尿液标本分离病毒，提取病毒RNA，通过RT—PCR扩增麻疹病毒N基因c末端456bp核苷酸并进行序列测定，与GenBank提供的麻疹各基因型参考株进行比较。结果2004年至2010年苏州市麻疹发病率为12．85／lO万，其中发病率最高为2005年，之后麻疹发病率开始下降。麻疹发病年龄主要集中在1岁以内及20～30岁两个年龄段，发病人群以散居儿童为主。从57例麻疹病例中分离到4株麻疹病毒株，其中3株为Hla型，与世界卫生组织（WHO）推荐的H1型基因代表株（China93—2、China93—7、China94—7）比较，同源性为98．46％～99．12％；而另1株则为A型，与A型代表株Shanghail91的同源性〉99％。结论2005年后苏州市麻疹发病率呈下降趋势，麻疹发病年龄主要集中在1岁以内及20～30岁两个年龄段。2009年至2011年苏州地区麻疹流行株主要由Hla基因型引起，但也分离到A基因型。

[Abstract] Objective To understand the incidence of measles and the genetic characteristics of epidemic strains in Suzhou city from 2004 to 2010, and to provide scientific basis for strengthened measles surveillance and elimination of measles. Methods Disease data of measles cases in Suzhou city during 2004 to 2010 were collected for epidemiological analysis. RNAs were extracted from measles virus isolated from throat swab specimens collected from suspected measles cases during 2009 to 2011. The 456 bp fragment of C terminus of nucleoprotein （N） gene was amplified by reverse transcriptase- polymerase chain reaction. Sequence analysis was conducted to ascertain the genotype and compare the difference of nucleotide with other measles virus strain registered in GenBank. Results The annual average incidence of measles was 12.85/100 000 during 2004 to 2010. Incidence of measles peaked in 2005 and then declined. Children younger than 1 year and adults 20- 30 years were dominantly infected. Migrant children were main cases of all cases. Four measles viruses were isolated from 57 throat swab specimens, and sequence analysis indicated that 3 of them belonged to Hla genotype. The456 nucleotides in the terminal of the N gene shared 98.46 0~_ 99.12~//00 homogeneity with the World Health Organization （WHO） recommend H1 genotype reference strains （China93-2, China93-7, and China94-7）. Another one of the 4 strains belonged to A genotype, with 99% genetic homogeneity compared with Shanghai191. Conclusions The incidence of measles declines after the year 2005. The majority of isolates are Hla genotype, while a genotype A strain is also isolated.