Biologia de cepas de <em>Trypanosoma cruzi</em> isoladas de pacientes chagásicos de diferentes origens geográficas residentes no noroeste do Paraná

Abstract

Thirty-one Trypanosoma cruzi strains isolated from chagasic patients from different geographic origins who were residing in the northwestern region of the state of Paraná at the time of the study. The strains were analyzed using biological parameters including infectivity of culture forms, parasitemia curves, mortality and histopathologic patterns in male C3H/He mice. In addition, metacyclogenic capacity and growth in LIT and M16 cultures were evaluated. From thirty strains infected mice, 27 had patent parasitemia and 3 had subpatent parasitemia. Of these 30 strains, 16 were maintained by blood passages (BP), 7 by alternate and post blood passages (AP/BP) and 7 by alternate passages (AP). Eight strains had parasitemia peaks of 10³ parasites/ml and 15 strains had peaks of 10⁴ - 10⁶ trypomastigotes/ml. It was not possible to measure this parameter for 7 strains. Three strains (PR 182, PR 1055, PR 501) caused mortality in mice. Histopathologic analysis revealed amastigote nests in the heart and skeletal muscle for PR 2259 and PR 182 strains respectively. The eight strains analyzed for this parameter induced inflammatory reactions in various organs. Epimastigote→trypomastigote differentiation rates for 21 analyzed strains were for the most part low. All strains were considered to have low-to-medium virulence. This homogeneity of biological behavior could be related to the fact that only strains isolated from humans were analyzed. Shortly, we intend to analyze other parameters and study T. cruzi strains isolated from triatomines and reservoirs from the northwestern region of the state of Paraná to compare to the human strains studied here.