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目的对山西省2006年报告的4例聚集性高危急性弛缓性麻痹(Acute Flaccid Paralysis,AFP)病例进行流行病学分析,并对采集的粪便标本中分离到的4株Ⅲ型脊髓灰质炎(脊灰)病毒(Poliovirus,PV)进行VP1编码区基因特征分析,以判断这起事件的性质。方法按照世界卫生组织《脊灰实验室手册》进行病毒分离与血清学定型,用逆转录-聚合酶链反应扩增VP1编码区基因片段,并进行核苷酸序列测定和分析,构建基因亲缘关系树。结果4例高危AFP病例中的3例为疑似疫苗相关麻痹型脊灰(Vaccine Associated Paralysis Poliomyelitis,VAPP),在发病时间上接近。4株Ⅲ型PV与疫苗参考株BJOPVⅢ相比,VP1编码区核苷酸同源性分别为99.7%、99.9%、99.4%、99.9%,均鉴定为疫苗相关株。基于VP1编码区核苷酸序列建立的进化树表明,4株PV之间无相关性,从3例VAPP中分离到的3株Ⅲ型PV在VP1编码区共享第2637位胞嘧啶核苷酸(C)→尿嘧啶核苷酸(U)突变位点,该位点变异导致氨基酸由缬氨酸(Val)突变为丙氨酸(Ala)。结论加强聚集性高危AFP病例和VAPP的实验室监测,早期发现PV循环并及时阻断。
Objective To analyze the epidemiological analysis of 4 cases of Acute Flaccid Paralysis (AFP) collected in Shanxi Province in 2006, and analyze the distribution of 4 strains of poliomyelitis Ⅲ Gray) virus (Poliovirus, PV) VP1 coding region of gene characteristics to determine the nature of the incident. Methods Virus isolation and serological typing were performed according to the “Polio Laboratory Manual” of the World Health Organization. The VP1 coding region gene fragment was amplified by reverse transcription - polymerase chain reaction (PCR) and the nucleotide sequence was determined and analyzed to establish the genetic relationship tree. Results Of the 4 high-risk AFP cases, 3 were suspected Vaccine Associated Paralysis Poliomyelitis (VAPP), which were close in onset time. Four strains of type III PV had 99.7%, 99.9%, 99.4% and 99.9% nucleotide homology with the vaccine reference strain BJOPVⅢ, respectively, and were identified as vaccine-related strains. Phylogenetic trees based on the nucleotide sequence of the VP1 coding region showed no correlation between the four PVs. Three type III PVs isolated from the three VAPPs shared the 2637th cytosine nucleotide in the VP1 coding region C) → uracil nucleotide (U) mutation site, this site mutation leads to the amino acid from val (Val) to alanine (Ala). CONCLUSIONS: To strengthen the laboratory monitoring of high-risk AFP cases and VAPP, early detection of PV circulation and timely blockade.