Echovirus 18 (E18),a serotype of Enterovirus B (EV-B) species,is an important pathogen in aseptic meningitis.El8 had rarely been detected in mainland China,but became the predominant pathogen associated with viral encephalitis (VE) and meningitis in Hebei province for the first time in 2015.To investigate the molecular epidemiology and genetic characteristics of El8 in mainland China,sixteen El8 strains from patient throat swabs with hand,foot,and mouth disease (HFMD) in six provinces in China collected between 2015 and 2016,and four El8 strains isolated from 18 patient cerebrospinal fluid specimens with VE in Hebei Province in 2015 were obtained and sequenced.Combined with the sequences from the GenBank database,we performed an extensive genetic analysis.Phylogenetic analysis of VP1 gene sequences revealed that all El8 strains from mainland China after 2015 belonged to subgenotype C2.There were no obvious specific differences in phylogenetic and variation analyses of El8 genome sequences between HFMD and VE/meningitis strains.Potential multiple recombination may have occurred in the 5\'-untranslated region and in the P2 and P3 nonstructural protein-encoding regions of El8 strains from China.The current El8 strains were potential multiplerecombinant viruses.Overall,these findings supported that E 18 caused HFMD,VE,and meningitis,although there were no significant associations between clinical features and viral genomic characteristics.