湖南省急性弛缓性麻痹病例分离株的性状分析

The Character of Polio Vaccine-associated Viruses from AFP Cases in Hunan Province

1 997～ 2 0 0 1年 ,湖南省疾病预防控制中心从急性弛缓性麻痹 (AFP)病例粪便标本中共分离到单型脊髓灰质炎(脊灰 )毒株 85株 ,经中国疾病预防控制中心病毒病预防控制所国家脊灰实验室用逆转录 聚合酶链反应 限制性酶切片长度多态性分析 (RT PCR RFLP)方法进行型内鉴定 ,全部为疫苗相关株。对其中从“零”剂次免疫患儿、有残留麻痹患儿和一些其他相关的患儿粪便标本中分离到的脊灰病毒进行了VP1区和 3D区的核苷酸序列测定。结果显示 :在脊灰Ⅱ型毒株中 ,绝大多数毒株在VP1区的核苷酸中第 2 90 9位位点发生突变 ,导致第 1 4 3位氨基酸由Ile变为Asn或Thr。在脊灰Ⅱ型毒株中 ,广泛存在着型间重组现象。在重组病毒中 ,以Ⅱ型与Ⅲ型病毒的重组为主 ,占 90 %。从AFP病例及健康儿童中 ,从有残留麻痹患儿及无残留麻痹患儿的粪便标本中 ,都能分离到重组株 ,说明重组的发生具有普遍性 ,重组发生的位点在核苷酸的不同位置 ,重组的形式又具有多样性。通过对湖南省毒株的碱基突变和重组的研究表明 ,在湖南省 1 997～ 2 0 0 1年的分离株不支持隔年传播 ,只在局部地区某一年内可能发生有限的循环。通过加强口服脊灰疫苗的免疫 ,提高免疫覆盖率 ,可以阻止疫苗相关病毒局限的循环。

In Hunan Province,during 1997 to 2001,there were 85 single type polioviruses isolated from the stool samples of AFP cases We selected some viruses,isolated from the'0'dose patients,the paralyzed residue patients and some other related patients,to analyze their VP1 and 3D regions of the genome The results showed that the 2909 th nt of most of the typeⅡ polioviruses had changed that made the 143 th amino acid change from Ile into Asn or Thr. In type Ⅱ polioviruses,another important phenomenon was the intertypic recombination Intertypic recombination of polioviruses occurred frequently during poliovirus evolution. In the recombinant viruses,most of those were type Ⅱ/type Ⅲ recombinant polioviruses,the recombination was very frequent and multiplex We can draw the conclusion that during the year 1997 to 2001,no virus in Hunan Province could transmit year after year,it could only cause limited circulation in local area,while OPV can stop circulation of vaccine associated polioviruses