Sarcocystis infection and myocardial pathological changes in cattle from south-eastern Norway.

The incidence of myocardial sarcocystis infection and of myocardial pathological changes was recorded in samples of 79 healthy cattle obtained from an abattoir. The incidence rate of thin-walled cysts of S. cruzi was 81.0 %, while mixed infection with thick-walled cysts of S. hominis and/or S. hirsuta was found in 5.0 %. Focal interstitial myocarditis was found in 31.6 % of the samples. The sarcocystis infection and the interstitial mononuclear cell infiltrates were positively associated (P < 0.05). Intimai proliferations of musculo-elastic or fibro-elastic tissues in the intramural coronary arteries were found in 75.0 % of the cattle older than 3% years of age, and in 45.7 of the cattle less than 3½ years old. No association of the arterial lesions and the sarcocystis infection was demonstrated.