Estudo comparativo dos indices de cura de camundongos tratados com quimioterapicos e trypanosominum (TC D 30) / Comparative analysis of the cure rate in mices treated with chemoterapics and trypanosominum (TC D 30)

ABSTRACT

Trypanosoma cruzi strain isolated from wild mamals or from man and studied in the laboratory show different characteristics that permit their individualization. Blood trypamastigotes exhibit different morphological patterns according to the strain studied. Tropism for different tissues has also been reported. Morphologically, there are wide, thin and intermediate forms wose proportions vary. The results obtained by different investigations in the treatment of Chagas disease are discrepant in different geographic areas, probably because of a relationship with different populations of T.cruzi. In the presentestudy, we investigated experimentally the susceptibility of two polar species, i.e. two species with predominance of thin and wide forms, respectively (Y e Bolivia strains) to the action of Nifurtimax, Benzonidazol and Trypanosaminum (TC D30). Groups of 30 mice aged 60 days were inoculated with 10.4 bloodstream forms of the Y and Bolivia strains of T.cruzi. On the third day of infection, the animals were treated with 100 mg/Kg of both chemotherapeutic agents and with 5 dropsof Trypanosaminum (TC D 30) orally for 20 days. Each animal was evaluated for parasitemia and behavior. Xenodiagnosis and blood cultures were carried out after 40 days. The results showed a) a sharp resistance of the Bolivia strain to the chemotherapeutic agents, while the Y strain was more susceptible; b) identical susceptibility of the Y and Bolivia strains to treatment with Trypanosominum. We infer from these data that the chemotherapeutic agents act on the parasitic formsby destroying them or not, with sharp differences when different populations areinvolved. In contrast, Trypanosaminum (TC D 30) may act on the stimulating the imunologic response, wich may destroy the etiologic agents through a specific response mechanism, regardless of the characteristics of the strain studied