II. SYMPTOMS AND SIGNS A. Acute Phase
In the acute phase of the disease, trypanosomes are found in the cardiac fibers accompanied by marked cellular infiltrate around cells that have ruptured and released the parasites. It is not unusual, however, to be unable to find parasites in the cardiac tissue at autopsy. An autoimmune mechanism is believed to explain the lack of correlation of parasitemia with disease severity. T. cruzi antigen is frequently found in biopsy specimens.