CHRONIC EXPERIMENTAL-INFECTION BY TRYPANOSOMA-CRUZI IN CEBUS-APELLA MONKEYS

Twenty young male Cebus apella monkeys were infected with CA I Trypano soma cruzi strain and reinfected with CAI or Tulahuen T. cruzi strains , with different doses and parasite source. Subpatent parasitemia was usually demonstrated in acute and chronic phases. Patent parasitemia w as evident in one monkey in the acute phase and in four of them in the chronic phase after re-inoculations with high doses of CAl strain. Se rological conversion was observed in all monkeys; liters were low,rega rdless of the methods used to investigate anti-T. cruzi specific antib odies. Higher liters were induced only,when re-inoculations were perfo rmed with the virulent Tulahuen strain or high doses of CAl strain. Cl inical, electrocardiographic and ajmaline test evaluations did not rev eal changes between infected and control monkeys. Histopathologically, cardiac lesions were always characterized by focal or multifocal mono nuclear infiltrates and/or isolated fibrosis, as seen during the acute and chronic phases; neither amastigote nests nor active inflammation and fibrogenic processes characteristic of human acute and chronic myo carditis respectively, were observed These morphological aspects more closely resemble those found in the ''indeterminate phase'' and contra st with the more diffuse and progressive pattern of the human chagasic chronic myocarditis. All monkeys survived and no mortality was observ ed.