Genotyping and identification of non-polio enterovirus isolates from acute flaccid paralysis cases in Chongqing in 2013-2020 / 公共卫生与预防医学

ABSTRACT

Objective To classify and identify the 53 strains of non-polio enterovirus (NPEV) isolated from acute flaccid paralysis (AFP) cases in Chongqing from 2013 to 2020, and to investigate the genotype distribution of the strains. Methods Commercial real-time fluorescence quantitative polymerase chain reaction (real-time PCR) reagents were used for rapid identification of the strains. The nucleotide sequences of VP1 and VP4 regions were used for genotyping. Results Fifty enteroviruses were identified, 33 (66%) in group A and 17 (34%) in group B. Group C and D enteroviruses were not found in these strains，and 3 strains could not be identified. In this study, EV-A71 was the dominant type, with 11 strains (22%), but EV-A71 strain was not isolated since 2016. The sequences of VP4 region and VP1 region were completely consistent in enterovirus grouping. Conclusion When using commercial real-time PCR reagents for enterovirus typing, the identification results of high CT values may be inaccurate. In the genotyping of enterovirus, the nucleotide sequence of VP4 region is first used for grouping, and then the nucleotide sequence of VP1 region is used for genotyping, which could simplify the experimental process. NPEV isolates from AFP cases in Chongqing showed poor genotype diversity. In order to enrich and improve the enterovirus gene database in Chongqing, it is necessary to carry out research on enterovirus transmitted by respiratory tract.