EMC viral infection of the coronary blood vessels in newborn mice: viral vasculitis.

The coronary arteries, veins and capillaries of newborn mice experimentally infected with encephalomyocarditis (EMC) virus were studied histologically and electronmicroscopically. Damage to these coronary vessels was patchy. Some lesions were extensive, particularly when adjacent to areas of myocardial damage. The histological findings consisted of swelling of adventitial and endothelial cells pyknosis, and polymorphonuclear leucocyte and round cell infiltration. Histological and ultrastructural changes occurred in all three layers of the vessels. EMC viral crystals were found electronmicroscopically in the adventitia of the coronary arteries and veins. Ultrastructural lesions typical of virocytonecrosis were frequently noted in association with viral crystals, establishing the viral etiology of the lesions. These findings lend support to the concept that the patchy atherosclerotic and arteriosclerotic lesions found in the coronary vessels of man may represent healed lesions of previous viral damage.