Encephalomyocarditis virus myocarditis in inbred strains of mice--chronic stage.

Inbred strains of A/J, BALB/c, C3H/He, C57BL/6 and DBA/2 mice were inoculated with the M variant of encephalomyocarditis virus having a titer of 100 TCID50/0.1 ml. Myocardial lesions were seen in 73 of 150 BALB/c mice (48.7%), 160 of 259 C3H/He mice (61.8%) and 115 of 174 DBA/2 mice (66.1%). No pathologic findings were noted in A/J and C57BL/6 mice. In C3H/He and DBA/2 mice, dilatation and hypertrophy of the heart accompanying myocardial lesions persisted up to the 8th month after virus inoculation. The present study revealed that myocardial lesions similar to those in congestive (dilated) cardiomyopathy persisted for a long period after viral infection.