Pathological and immunohistochemical findings of a case of canine chagasic myocarditis in the state of Mato Grosso

Dogs are as considered important reservoirs of trypanosomiasis and play a vital role in maintaining the interaction between the domestic and wild cycles of this disease. This paper reports the clinical and pathological findings of a case of Chagas disease myocarditis in a dog from an urban area in Brazil. During clinical examination, the animal showed apathy, weakness and pale ocular mucous and died shortly after. Necropsy revealed ascites, hydrothorax and hydropericardium. The heart was remarkably globoid with scattered multifocal pale in the epicardium and ventricular miocardium and dilated chambers. Histological analysis revealed non-suppurative myocarditis and cardiomyocyte necrosis. The sarcoplasms of cardiomyocytes were frequently infiltrated by T. cruzi pseudocysts filled with amastigotes. The myocardium immunostained positive for anti- T. cruzi antibody. The presence of Chagas disease in a dog from an urban area increases the risk of disease transmission to man, which renders this diagnosis a matter of significant public health concern.