福建省脊髓灰质炎Ⅱ型疫苗重组株病毒特性与分析

Characteristics and Analysis of Recombinant Type Ⅱ Vaccine Poliovirus in Fujian Province

对福建省脊髓灰质炎 (脊灰 )Ⅱ型病毒基因的VP1区和 3D区进行PCR -RFLP分析 ,结果有 5株为脊灰Ⅱ型疫苗重组株病毒 ,均表现为VP1区为Ⅱ型疫苗株 ,3D区为Ⅲ型疫苗株 ,有 4株在VP1区出现不同于标准脊灰Ⅱ型疫苗株病毒的变异。流行病学资料揭示 ,分离出脊灰Ⅱ型重组株病毒的急性弛缓性麻痹 (AFP)病例大多具有脊灰的症状 ,且发病表现出明显的季节性 ;而从“零”剂次免疫儿童或近 6个月从未服过脊灰疫苗儿童的粪便标本中 ,只分离到此病毒。这表明福建省自然环境中存在脊灰Ⅱ型疫苗重组株病毒循环 ,此病毒可能是这类AFP病例的致病因子。在我国保持无脊灰状态下如何控制脊灰Ⅱ型重组株病毒的致病 ,适时采取相应对策对今后的工作提出了新的挑战。

We analyzed VP1 and 3D fragment coding regions of type Ⅱ polioviruses isolated in Fujian Province in 1999-2000 from acute flaccid paralysis(AFP)cases by PCR-RFLP.5 of the 9 isolated strains were recombinant type Ⅱ polioviruses,they all displayed Sabin Ⅱ charaeteristics in VP1 region and Sabin Ⅲ in 3D region.The other 4 strains showing changes in one restriction site in VP1 fragment were type Ⅱ vaccine-derived polioviruses.The epidemiological data showed that most of the AFP cases from whom the recombinant type Ⅱ polioviruses were isolated had the similar symptoms like polio patients,the cases obviously had typical seasonal peak and these recombinant type Ⅱ polioviruses only were isolated from fecal specimens of children who had zero-dose oral polio vaccine(OPV)or never had OPV in recent six months.The study indicated that there were type Ⅱ recombinant polioviruses circulating in the natural environment of the province and they possibly could be the pathogenic factor of AFP.For keeping a polio-free state of our country,it would be a new challenge for us to adopt corresponding strategy to control the pathogenicity of these recombinant type Ⅱ polioviruses.