The role of enterovirus replication in the development of acute and chronic heart muscle disease in different immunocompetent mouse strains.

In order to study interrelationships between virus replication and the development of acute and chronic heart disease, different immunocompetent mouse strains (A.CA/SnJ, A.BY/SnJ, SWR/J, DBA/1J) were infected with coxsackievirus B3 (CVB3). Based on in situ hybridization, patterns of acute and persistent infections were quantitated in the representative mouse strain A.CA/SnJ by application of computer-assisted digital image processing and correlated with the extent of myocardial injury and cellular immune response. Here we show that the acute infection is characterized by virus-induced myocytolysis with increasing densities of inflammatory mononuclear cells, whereas persistent infection reveals a decreased number of infected myocardial cells in the presence of a reduced but ongoing inflammation. The major role of viral replication in the pathogenesis of acute and chronic heart disease is substantiated by the finding that tissue lesions as well as inflammation consistently developed at the sites of virus replication. No inflammatory lesions were observed to evolve independently of virus replication, indicating that persistent infection is essential for the development of chronic disease. The availability of a murine model of ongoing CVB3-induced myocarditis should prove to be useful for further studies on molecular mechanisms of enterovirus persistence, e.g. with regard to myocyte metabolism in persistently infected cells or identification of host genes involved in the pathogenesis of chronic enterovirus-induced cardiomyopathy.