Epidemiologic and genetic characteristics of coxsackievirus A6 strains isolated in Shenyang from 2013 to 2017

Objective To study the epidemiologic and genetic characteristics of coxackievirus A6(CV-A6) strains isolated in Shenyang. Methods Enterovirus strains positive for neither enterovirus A71 (EV-A71) nor CV-A16 were isolated from Shenyang during 2013 to 2017 to screen for CV-A6 isolates by real-time PCR. The entire sequences of viral genes encoding VP1 of CV-A6 positive samples were amplified and sequenced. The phylogenetic analysis was performed. Results CV-A6 strains accounted for 27.83% (575/2 066) of the non-EV-A71 and non-CV-A16 enterovirus strains isolated in Shenyang during the years 2013 to 2017. And CV-A6 strains were the predominant enterovirus strains with positive rate of 68.38 % (240/351) in 2015. The CV-A6 isolates from Shenyang during 2013 to 2017 could be classified into the cluster D3a in the phylogenetic tree. Subtype D3a.1 strains circulated during 2013 to 2014 and subtype D3a.2 strains circulated during 2015 to 2017. Conclusions CV-A6 strains were the predominant enterovirus strains among non-EV-A71 and non-CV-A16 enterovirus strains circulated in Shenyang from 2013 to 2017. The CV-A6 isolates from Shenyang during 2013 to 2017 could be classified into the cluster D3a in the phylogenetic tree and subtype D3a.2 strains were evolved from subtype D3a.1 strains.