Liu H M, Zheng D P, Zhang L B, Oberste M S, Pallansch M A, Kew O M
Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
J Virol. 2000 Dec;74(23):11153-61. doi: 10.1128/jvi.74.23.11153-11161.2000.
Type 1 wild-vaccine recombinant polioviruses were isolated from poliomyelitis patients in China from 1991 to 1993. We compared the sequences of 34 recombinant isolates over the 1,353-nucleotide (nt) genomic interval (nt 2480 to 3832) encoding the major capsid protein, VP1, and the protease, 2A. All recombinants had a 367-nt block of sequence (nt 3271 to 3637) derived from the Sabin 1 oral poliovirus vaccine strain spanning the 3'-terminal sequences of VP1 (115 nt) and the 5' half of 2A (252 nt). The remaining VP1 sequences were closely (up to 99.5%) related to those of a major genotype of wild type 1 poliovirus endemic to China up to 1994. In contrast, the non-vaccine-derived sequences at the 3' half of 2A were more distantly related (<90% nucleotide sequence match) to those of other contemporary wild polioviruses from China. The vaccine-derived sequences of the earliest (April 1991) isolates completely matched those of Sabin 1. Later isolates diverged from the early isolates primarily by accumulation of synonymous base substitutions (at a rate of approximately 3.7 x 10(-2) substitutions per synonymous site per year) over the entire VP1-2A interval. Distinct evolutionary lineages were found in different Chinese provinces. From the combined epidemiologic and evolutionary analyses, we propose that the recombinant virus arose during mixed infection of a single individual in northern China in early 1991 and that its progeny spread by multiple independent chains of transmission into some of the most populous areas of China within a year of the initiating infection.
1991年至1993年期间，在中国从脊髓灰质炎患者中分离出1型野生疫苗重组脊髓灰质炎病毒。我们比较了34株重组分离株在编码主要衣壳蛋白VP1和蛋白酶2A的1353个核苷酸（nt）基因组区间（nt 2480至3832）上的序列。所有重组体都有一个367 nt的序列块（nt 3271至3637），源自Sabin 1口服脊髓灰质炎疫苗株，跨越VP1的3'末端序列（115 nt）和2A的5'半部分（252 nt）。其余的VP1序列与1994年以前在中国流行的1型野生脊髓灰质炎病毒主要基因型的序列密切相关（高达99.5%）。相比之下，2A 3'半部分的非疫苗衍生序列与来自中国的其他当代野生脊髓灰质炎病毒的序列关系更远（核苷酸序列匹配度<90%）。最早（1991年4月）分离株的疫苗衍生序列与Sabin 1完全匹配。后来的分离株与早期分离株的差异主要是由于在整个VP1-2A区间积累了同义碱基替换（每年每个同义位点的替换率约为3.7×10^(-2)）。在中国不同省份发现了不同的进化谱系。综合流行病学和进化分析，我们提出重组病毒于1991年初在中国北方一名个体的混合感染期间出现，其后代在初始感染后的一年内通过多条独立的传播链传播到中国一些人口最密集的地区。
