The canine model of Chagas' disease

Immunopathology of Chagas disease

“…The role of a vascular factor in acute Chagas myocarditis has been emphasized, especially by investigators who observed platelet thrombi within myocardial capillaries of mice (Rossi et al 1984, Tanowitz et al 1990). However, the ultrastructural signs of cytotoxic damage to the myocytes seen in the canine model far exceeded those indicative of ischemic injury (Andrade 1984). On the other hand, microangiopathy appears as an important clue suggesting the participation of cytokines in acute Chagas myocarditis.…”

“…The dog is an exception. Young dogs usually develop severe acute disease when naturally or experimentally infected with T. cruzi (Andrade 1984). When acute manifestations abate, a period of latent infection follows and may last for life.…”

Chagas' heart disease

“…Necropsy findings in humans have been correlated with observations in several animal models of experimental Chagas' disease reproducing the various stages of the disease 43,[78][79][80][81][82][83][84][85][86] . Endomyocardial biopsy has also been used in subsets of the chagasic population, including patients in the indeterminate phase 46,87 .…”

“…There is no relation between the frequency of apical aneurysm and age or heart weight, and aneurysms have been reported even in patients who died suddenly, with no apparent previous clinical manifestations of disease 44 . Histologic examination reveals mild chronic myocarditis, manifested by scattered mononuclear cell infiltrates with the surrounding myocytes undergoing various stages of degeneration and necrosis 82,89 . These changes have been traditionally interpreted as not being related to direct parasitism of myocardial cells, since intact parasites are rarely detected in humans and in experimental models of Chagas' disease 82 .…”

Impaired autonomic control of heart interval changes to Valsalva manoeuvre in Chagas' disease without overt manifestation

“…The human and experimental indeterminate forms present less conspicuous lesions of cardiac intrinsic innervation, which are usually represented by discrete to moderate focal or zonal chronic neuroganglionitis (Lopes and Tafuri, 1983;Andrade, 1984;Oliveira, 1985;Chapadeiro et al, 1991). Cardiac autonomic damage has also been observed in acute and chronic experimental Trypanosoma cruzi infection in mice (Tafuri, 1970;Souza et al, 1996), dogs (Andrade, 1984;Machado et al, 1998), rats (Chapadeiro et al, 1991;Junqueira et al, 1992), and hamsters (Chapadeiro et al, 1999) among other animal models.…”