Using SimPlotß [37] , the HRV A2 sequences were found to be most similar to those from HRV A strains (54% identity) whereas identity with HEV species ranged from 46%-49% ( Figure 1B ). Dips in identity occurred across all regions but only the structural region was investigated further because its components contain antigenic sites and receptor contact residues, or 'footprints'; the latter being significant domains for defining the major and minor group HRVs [38] and other picornaviruses.