title: Molecular evolution of a type 1 wild-vaccine poliovirus recombinant during widespread circulation in China.
abstract: 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.
authors.affiliation: Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. hdl1@cdc.gov
authors.forename: H M
authors.initials: HM
authors.lastname: Liu
authors.forename: D P
authors.initials: DP
authors.lastname: Zheng
authors.forename: L B
authors.initials: LB
authors.lastname: Zhang
authors.forename: M S
authors.initials: MS
authors.lastname: Oberste
authors.forename: M A
authors.initials: MA
authors.lastname: Pallansch
authors.forename: O M
authors.initials: OM
authors.lastname: Kew
mesh_terms: D001483:Base Sequence; D005075:Biological Evolution; D002213:Capsid / Q000235:genetics*; D036022:Capsid Proteins; D003546:Cysteine Endopeptidases / Q000235:genetics*; D008969:Molecular Sequence Data; D017955:Poliovirus / Q000235:genetics* / Q000276:immunology; D011995:Recombination, Genetic; D014764:Viral Proteins
chemical_list: D036022:Capsid Proteins; C442540:VP1 protein, Poliovirus; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C057400:picornain 2A, Picornavirus