Morphological, biological and molecular characterization of three strains of Trypanosoma cruzi Chagas, 1909 (Kinetoplastida, Trypanosomatidae) isolated from Triatoma sordida (Stal) 1859 (Hemiptera, Reduviidae) and a domestic cat

SUMMARY

A study was conducted of the biological, morphological and molecular characters of 3 strains of Trypanosoma cruzi (SI ₅, SI ₈ and SIGR ₃) isolated from specimens of Triatoma sordida collected in Santo Inácio and a domestic cat. In order to carry out the study, the following parameters were evaluated: pre-patent period, parasitaemia curves, morphology of the parasites, mortality rates, histopathological lesions and molecular typing. The strains presented variable pre-patent periods, low parasitaemia and no animal mortality. The morphological study of trypomastigotes showed a predominance of intermediate-width and short-length forms, as well as low nuclear index. Epimastigotes presented a low nuclear index, intermediate-width forms in strains SI ₅ and SI ₈, and large-width forms in SIGR ₃. A shorter length could be noted in strains SI ₈ and SIGR ₃, whereas SI ₅ displayed an intermediate length. The histopathological study did not detect amastigote nests in tissues. The amplification of the divergent domain of 24S α rRNA, HSP60 and GPI genes of strains SI ₅, SI ₈ and SIGR ₃ classified the 3 strains into Group II. Biological parameters made it possible to classify the strains isolated in Santo Inácio (BA) into Biodeme III, Zymodeme 1 and Group II of T. cruzi.