Recombinant enteroviruses for use as vaccines or vectors, which are modified in tropism or virulence, are disclosed. Also disclosed are DNA constructs comprising enterovirus-derived molecular determinants of tropism or virulence for use in targeting genes of interest to specific cells or tissues. The recombinant enteroviruses and DNA constructs comprise molecular determinants of tropism and virulence localized in specific domains of the 5'NTR of the enteroviral genome.