Mengovirus, Columbia SK virus and mouse Elberfield virus are best regarded as strains of EMCV, based on serological cross-reaction and sequence identity. Theiler's encephalomyelitis virus, also known as murine poliovirus, has 54% nucleotide sequence identity with EMCV and less than 40% with other picornavirus groups. The location and nature of its antigenic sites are comparable to those of the other cardioviruses.