Chronic experimental infection by Trypanosoma cruzi in Cebus apella monkeys

Twenty young male Cebus apella monkeys were infected with CAl Trypanosoma cruzi strain and reinfected with CA l or Tulahuen T.cruzi strains, with different doses and parasite source. Subpatent parasitemia was usually demonstrated in acute and chronic phases. Patent parasitemia was 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. Serological conversion was observed in all monkeys; titers were low, regardless of the methods used to investigate anti-T. cruzi specific antibodies. Higher titers were induced only when re-inoculations were perfomed with the virulent Tulahuén strain or high doses of CAl strain. Clinical electrocardiographic and ajmaline test evaluations did not reveal changes between infected and control monkeys. Histopathologically, cardiac lesions were always characterized by focal or multifocal mononuclear 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 myocarditis respectively, were observed. These morphological aspects more closely resemble those found in the "indeterminate phase" and contrast with the more diffuse and progressive pattern of the human chagasic myocarditis. All monkeys survived and no mortality was observed.

Chronic experimental infection by Trypanosoma cruzi in Cebus apella monkeys.

Twenty young male Cebus apella monkeys were infected with CA1 Trypanosoma cruzi strain and reinfected with CA1 or Tulahuen T. cruzi strains, with different doses and parasite source. Subpatent parasitemia was usually demonstrated in acute and chronic phases. Patent parasitemia was evident in one monkey in the acute phase and in four of them in the chronic phase after re-inoculations with high doses of CA1 strain. Serological conversion was observed in all monkeys; titers were low, regardless of the methods used to investigate anti-T. cruzi specific antibodies. Higher titers were induced only when re-inoculations were performed with the virulent Tulahuén strain or high doses of CA1 strain. Clinical, electrocardiographic and ajmaline test evaluations did not reveal changes between infected and control monkeys. Histopathologically, cardiac lesions were always characterized by focal or multifocal mononuclear 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 myocarditis respectively, were observed. These morphological aspects more closely resemble those found in the "indeterminate phase" and contrast with the more diffuse and progressive pattern of the human chagasic chronic myocarditis. All monkeys survived and no mortality was observed.

Experimental Argentine hemorrhagic fever: myocardial involvement in Cebus monkey.

Four Cebus apella monkeys, to test a recently proposed model for testing neurovirulence of Junín virus (JV) strains, were intracerebrally infected with 10(5) LD50 of the XJ clone 3 strain of JV. There were no significant electrocardiographic abnormalities or gross lesions, but all infected monkeys exhibited a varying degree of histologic myocardial lesions including focal lymphoblastic infiltrates, vascular ruptures, and mild interstitial reactive change. One Cebus showed lymphocytic infiltrates in the caudal portion of the A-V node without specific cell involvement. These preliminary results demonstrate cardiac involvement in experimental infection of the Cebus monkey with Junín virus.

Aging jejunal vascular ectasia as a cause of persistent intestinal bleeding.

Undiagnosed gastrointestinal bleeding is a major problem in medical practice. This paper describes a patient with vascular intestinal ectasia who had repeated severe intestinal hemorrhages for two years, and required surgery. Vascular intestinal ectasia was demonstrated radiologically, histologically and by electron microscopy in a 25 cm upper jejunum resection. The absence of ultrastructural alterations in intestinal vessels points out that the term "aging vascular ectasia" (Moore Type I) seems preferable, when Rendu Ossler, Von Willebrand and intestinal hemangioma are discarded.

Experimental Chagas disease in a South American primate (Cebus sp).

Two year old Cebus sp monkeys were infected with the Argentine strain of T. cruzi by the conjuctival route employing metacyclic forms of the parasite, obtained from dejecta of T. infectans. Both animals developed parasitemia detected by xenodiagnosis, without any overt acute disease, and with serological conversion. After 9-10 months of infection, both animals developed significant ECG abnormalities. One animal died spontaneously and the other was sacrificed. At necropsy, both animals presented significant megacolon. Severe thinning of the intestinal wall was observed without inflammatory lesions and with preservation of the parasympathetic plexus. Histologic studies revealed fibrotic lesions in the myocardium. In this organ, lymphocytic infiltrates were found in infrequent and small foci, but no pseudocytic forms containing parasities were observed. These observations suggest that the Cebus monkey may be a useful experimental model for some major aspects of chronic Chagas disease in man.