1. [Genetic Characteristics of Type 2 Vaccine-derived Poliovirus in Shanxi Province (China) in 2014].
- Author
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Yan D, Li X, Zhang Y, Yang J, Zhu S, Wang D, Zhang C, Zhu H, and Xu W
- Subjects
- Amino Acid Sequence, Base Sequence, Capsid Proteins chemistry, Capsid Proteins genetics, China, Humans, Infant, Male, Molecular Sequence Data, Phylogeny, Poliovirus chemistry, Poliovirus metabolism, Poliovirus Vaccines adverse effects, Poliovirus Vaccines chemistry, Poliovirus Vaccines metabolism, Sequence Alignment, Poliomyelitis virology, Poliovirus genetics, Poliovirus Vaccines genetics
- Abstract
The World Health Organization redefined the type 2 vaccine-derived poliovirus (VDPV) in 2010. To study the genetic characteristics and evolution of type 2 VDPV under this new definition, we conducted genome sequencing and analyses of type 2 VDPVs isolated from one patient with acute flaccid paralysis in Shanxi province (China) in 2014. Nucleotide sequencing revealed that the full-length of type 2 VDPV is 7439 bases encoding 2207 amino acids with no insertion or deletion of nucleotides compared with Sabin2. One nucleotide substitution identified as a key determinant of the attenuated phenotype of the Sabin 2 strain (A-G reversion at nucleotide nt 481 in the 5-end of the untranslated region) had reverted in the Shanxi type 2 VDPV. The other known key determinant of the attenuated phenotype of the Sabin 2 strain (U-->C reversion at nt2909 in the VP1 coding region that caused a Ile143Thr substitution in VP1) had not reverted in the Shanxi VDPV. The Shanxi type 2 VDPV was S2/S1 recombinant, the crossover site of which mapped to the 3-end of the 3D region (between nt 6247 and nt 6281). A phylogentic tree based on the VP1 coding region showed that evolution of the Shanxi type 2 VDPV was independent of other type 2 VDPVs detected worldwide. We estimated that the strain circulated for approximately = 11 months in the population according to the known evolution rate. The present study confirmed that the Chinese Polio Laboratory Network could discover the VDPV promptly and that it played an important part in maintenance of a polio-free China.
- Published
- 2015