Cardiovirus specific sequences located in the 5' NTR are used to amplify viral RNA by PCR. General primers were selected for the amplification of cardioviruses, including encephalomyocarditis virus (EMCV), mengovirus and Theiler's murine encephalomyelitis virus (TMEV. Additionally, ECHO virus type 22, an atypical enterovirus, could also be detected with the general cardiovirus primers. An internal encephalomyocarditis virus specific probe and a general cardiovirus probe are used to discriminate EMCV from other cardioviruses. The sensitivity of the PCR was determined at 10 pfu after hybridization with an internal oligonucleotide probe. Specificity was tested with a broad range of picornaviruses and other nonrelated RNA and DNA viruses. The applicability of the assay was demonstrated by the detection of TMEV RNA in tissue samples from experimentally-infected mice.