Isolation of an imported subgenotype B5 strain of human enterovirus A71 in Chongqing City, China, 2014

BACKGROUND: Enterovirus A71 (EV-A71) is the main pathogen responsible for large outbreaks of hand, foot, and mouth disease (HFMD) in mainland China, and the dominant EV-A71 strains belong to subgenotype C4. To date, only one imported subgenotype B5 of EV-A71 has been reported in Xiamen City Fujian Province, 2009. RESULTS: Here, we report on another imported subgenotype B5 of EV-A71 isolated from a HFMD patient in Chongqing City in 2014 (strain CQ2014-86/CQ/CHN/2014, hereafter refer as CQ2014-86). The VP1 coding sequence and the whole genome sequence revealed that strain CQ2014-86 shares the high nucleotide identity with Vietnamese strains isolated in 2011–2013, suggesting that strain CQ2014-86 may have been imported from Vietnam. In the 5’UTR, P2 and P3 regions, recombination events were found between strain CQ2014-86 and other EV-A, such as coxsackievirus A4 (CV-A4), CV-A5, CV-A14 and CV-A16. CONCLUSIONS: This is the second report on importation of subgenotype B5 of EV-A71 in China, implying that we need to pay more attention to the importation of different subgenotypes of EV-A71.