Murine cytomegalovirus infection model in Balb/c mice--2. Pericarditis with myocardial involvement during virus infection.

Pericarditis with myocardial involvement was observed in mice infected with doses of murine cytomegalovirus (MCMV) designed to produce lethal, acute but non-lethal and asymptomatic infections. White spot was noted on the surface of the right ventricle from 4 to 6 days after MCMV infection. MCMV was isolated from the heart tissues as early as 2 days after infection. The virus titre reached a peak on day 6 and thereafter rapidly declined to undetectable level. Histopathological changes appeared on day 2 to 4 when necrosis of myocardial fibres occurred in the subpericardial region. This was followed by acute inflammatory cellular infiltration on day 6. After that organization of fibrin took place and fibrotic lesion and cellular infiltration could still be observed after 18 days. The pathological changes could only be seen in the right ventricle. Peroxidase-labelled antibody technique was carried out to detect MCMV antigen in the cardiac tissue. MCMV antigen was found in the pericardium only at the early stage of infection.