Concordancia de lesiones histológicas en ratones infectados por dos poblaciones de Trypanosoma cruzi de Chile / Prepatency, parasitemia and histological lesions in mice infected with two Trypanosoma cruzi populations isolated in Chile

Background:The great variability in the clinical presentation of Chagas disease may depend in part in the genetic variability of Trypanosoma cruzi populations. Aim: To compare prepatent period, parasitemia, mortality and histological lesions in mice infected with two populations of Trypanosoma cruzi isolated in Chile. Material and methods: Two Trypanosoma cruzi populations, isolated from Chilean Triatomides and genetically characterized by kinetoplast restriction fragment DNA profiles, were compared. Two groups of 40 Balb/c mice were studied. Each mouse was inoculated with 104 trypomastigotes, of the V-121 and sp COMB 2 Trypanosoma cruzi populations. The prepatent period, parasitemia, mortality and histopathological lesions, at different evolutionary stages of infection were registered during 32 days. Results: Prepatency and mortality were similar in both groups of mice. However, parasitemia was significantly greater in mice inoculated with V-121 than those inoculated with sp COMB 2. Amastigote pseudocysts and inflammation were present only in skeletal muscle and myocardium in both groups of mice. The intensity of tissue involvement was associated to the level of parasitemia, therefore it was greater in mice inoculated with V-121 population. Conclusions: V-121 population of Trypanosoma cruzi caused a greater parasitemia than COMB 2, in inoculated mice.

Poblaciones de trypanosoma cruzi altamente homogéneas en una región de baja endemia chagásica: relevancia en la patogenia de la enfermedad de Chagas en Chile / Highly homogeneous trypanosoma cruzi populations in a low endemic region for Chagas disease: importance in the pathogenesis of Chagas disease in Chile

Trypanosoma cruzi from 23 chronic and acute cases of Chagas dosease were isolated and further characterized. They displayed a remarkable similarity, after typification by schizodeme analysis using restriction endonuclease Eco Ri. All trypanosoma cruzi isolates belonged to the isoenzymatic Zymodeme 2 Bol. These findings were corroborated analyzing cases from families with demonstrated congenital transmission. The acute cases were newborns or offspring of infected mothers or patients with AIDS. All trypanosoma cruzi strains isolated in theses cases were very similar with almost identical schizodemes. Patients with AIDS had severe clinical manifestations whereas children with congenital infections had a great variety of clinical symptoms. In chronic cases, little clinical differences were observated for the different trypanosoma cruzi strains. It is concluded that there is a low correlation between the trypanosoma cruzi strain and the clinical prognosis of Chagas disease, being of greater relevance the host's genetic background and inmune response