Immunohistochemical chemical detection of encephalomyocarditis virus (EMCV) antigen in the heart of experimentally infected piglets

Seven 40-day-old piglets were inoculated with encephalomyocarditis virus (E MCV) strain 424/90, isolated from an outbreak of the myocardial form of the disease in Greece. Two non-infected animals were used as controls. Of the seven inoculated piglets, five died suddenly on day 1.5, 2 (two piglets), 2 .5 or 4 post inoculation (p.i.). The remaining two and the control piglets were killed on day 8 p.i. EMCV antigen was detected immunohistochemically i n endothelial cells of capillaries from 1.5 to 2.5 days p.i. only, but was found in cardiac muscle cells, Purkinje fibres and macrophages on all occas ions up to day 8 p.i. In endothelial cells and macrophages, EMCV antigen wa s detected intracytoplasmically; but in cardiac muscle cells and Purkinje f ibres it was observed intracytoplasmically or intranuclearly, or both. The Frequent presence of EMCV antigen in Purkinje fibres suggests an explanatio n for the sudden death of the piglets. (C) 2000 Harcourt Publishers Ltd.