The pathogenic constitution of HFMD cases and the genetic characteristics of enterovirus 71 in Hebei

Abstract

Objective To understand the pathogen composition and the EV71 genetic characteristics of different hand-foot-mouth disease(HFMD) patients in different areas of Hebei Province.Methods Virus isolation and nucleic acid detection were carried out on stool specimens,anal swab specimens,throat swab specimens,vesicle fluid specimens collected from the patients with HFMD disease.The VP1 genes of a total of Enterovirus 71 (EV71) strains were amplified by RT-PCR with specific primer pairs,then the PCR amplification products were sequenced to perform nucleotide sequence homology analysis and construct the phylogenetic tree with 38 genotype and subgenotype representative strains for analyzing the gene subtype and variation in Hehei province.Results Enterovirus positive rate was 65.13％ of clinical diagnosis of HFMD cases in Hebei Province in 2009.EV71 is the primary pathogen of HFMD,which accounted for 58.0％ of EV positive cases.Qinhuangdao,Handan,Baoding and Xingtai had a high proportion of EV71,while Hengshui and Cangzhou were major in CA16.The EV71 positive rate of normal cases was 37.74％,and the rate of severe cases was 80.64％.And EV71 was detected in all the 13 dead cases.The homogeneity of VP1 nucleotide sequence of the 18 separated EV71 strains from Hebei Province was 94.4％～99.8％.While compared with C4 subgenotypes,the homogeneity was 91.9％ ～99.6％.Conclusion EV71 and CA16 are the primary pathogen of HFMD of Hebei Province in 2009.Qinhuangdao,Handan,Baoding and Xingtai had a high proportion of EV71,while Hengshui,Langfang and Cangzhou were major in CA16.The EV71 strains belong to C4a evolution branch of C4 subgenotype by analyzing the EV71 and CA16 genetic characteristics and phylogenetic tree. Key words: HFMD; EV71; RT- PCR; Genetic characteristics