Molecular identification of non-polio enteroviruses in acute flaccid paralysis cases in Henan Province of China in 2019 / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the types and distribution of non-polio enterovirus (NPEV) in acute flaccid paralysis (AFP) cases in Henan Province in 2019.Methods:A total of 513 cases of AFP were reported in Henan Province in 2019. Two stool specimens were collected from each case for virus isolation. The VP1 gene of NPEV-positive strains was amplified and sequenced. Sequence alignment and construction of the phylogenetic tree were completed by MEGA5.1 software. The epidemiological data of NPEV-positive strains were statistically analyzed by Excel 2016 and SPSS19 software.Results:A total of 39 NPEV strains were isolated from 513 AFP cases, with an isolation rate of 7.60% (39/513). Among them, 18 strains were group A viruses and 21 strains were group B viruses. Both group A and group B viruses contained seven serotypes. No viruses of group C and group D was isolated. Coxsackievirus A type 4 (CVA4) and CVA16 were the predominant types in group A, and echovirus type 11 (Echo11) was the predominant type in group B. The nucleotide identity between the NPEV-positive strains was 67.4%-100.0%, and their nucleotide identity with the prototype strain was 71.4%-85.6%. NPEV was mainly detected in scattered children under 7 years old with an isolation rate of 84.62% (33/39), and the ratio of male to female was 2.07∶1. No statistically significant difference in the isolation rate was found between different age groups or between different sexes ( P>0.05). Among the group A viruses, CVA2, CVA4 and CVA16 were widely distributed. Echo3, Echo11 and Echo30 were the widely distributed group B viruses. NPEV could be isolated throughout the year except for January. Group A virus infections mainly occurred from April to July, accounting for 66.67% (12/18) of the whole year. Group B virus infections mainly occurred in September, accounting for 28.57% (6/21) of the whole year. Conclusions:The main serotype of NPEV isolated in Henan Province in 2019 was Echo11. The pathogen spectrum and regional distribution of NPEV as well as the isolation rate in different age groups changed significantly compared with those in 2018. Therefore, it was necessary to strengthen monitoring and conduct targeted prevention and control to effectively reduce the occurrence of AFP.