Trypanosoma rangeli (Tejera, 1920): observations upon pleomorphism

Abstract

Meta-trypomastigotes of Trypanosoma rangeli Tejera, 1920, harvested from LIT medium, were inoculated i.p. or s.c. into 6, 16, and 26 g NMRI mice, these representing increasing degrees of immunological maturity. In all cases, similar pleomorphic patterns were observed. Four morphobiometrically differentiable types of trypanosome were encountered in an overlapping temporal sequence. These observations, taken in comparison with those on pleomorphism in this and other species of Trypanosoma by other workers, are consistent with the hypothesis that the pleomorphic types represent the natural development of the parasite, rather than the result of the immune response of the mammal host. Small, slender trypanosomes prevalent at the onset of the parasitemia either reinvade the tissue cells for relatively limited subsequent generations of tissue reproduction, or else differentiate toward the forms that are only capable of colonizing the insect vector.

Morphological Features of Trypanosomes from Squirrel Monkeys from the Brazilian Amazon

“…3a) were typical forms, similar in dimensions and feature to those described by other authors in human and non-human primates, rodents, and marsupials, both naturally and artificially infected (Table I and Fig. 3b,c; Groot et al 1951, Herbig-Sandreuter 1957, Deane 1958, D'Alessandro 1976, Miles et al 1983, Steindel et al 1991, Urdaneta-Morales & Tejero 1992. The T. rangeli trypomastigotes we detected in the blood of squirrel monekys and marmosets had a mean length of 30.9 µm, were narrower (width of 1.9 µm) and, had a cytoplasm paler than those belonging to both T. minasense and T. saimirii-like.…”

“…The morphometry and the general features did not assure the identification of this parasite. The pleomorphism previously described in T. rangeli (Herbig-Sandreuter 1957, Hoare 1972, D'Alessandro 1976, Miles et al 1983, Steindel et al 1991, Urdaneta-Morales & Tejero 1992) also includes blood trypomastigotes that are wider (0.9-5.1 µm), longer (9.3-39 µm), and sometimes with a greater distance between the posterior end and the kinetoplast (0.5-8 µm), with a well-developed undulating membrane and a vacuoled, densely stained cytoplasm. Such robust or "mature" forms of T. rangeli, with a large PK, have dimensions and feature that are similar to those of trypanosomes identified as T. saimirii in the blood of squirm m rel monkeys (Tables I, II).…”

Serological Diagnosis of Trypanosoma rangeli Infected Patients. A Comparison of Different Methods and its Implications for the Diagnosis of Chagas' Disease

“…Peptide SAPA 1-B is a 50-aa peptide containing four repeats with natural variations and peptide SAPA 79 is a 50-aa peptide that covers the trans-sialidase motive; both are also contained within the complete SAPA antigen [31]. (2) fresh preparations revealed the typical unidirectional movement of T. rangeli; (3) stained flagellates had the T. rangeli characteristic small kinetoplast and the long, pointed posterior end [35,36]; (4) salivary glands from triatomine bugs were full of parasites and the fed group demonstrated no parasite content in their faeces within the month of evaluation [36,37]; and (5) cocultures of VERO cells and parasites showed no evidence of infection within the 3-4 weeks of study.…”

Action of Trypanosoma rangeli in infections with virulent Trypanosoma cruzi populations

“…Under natural conditions T. cruzi infects in the American continent over 100 mammalian species from different orders, including domestic and sylvatic animals (Teixeira et al 2001). T. rangeli, an assumed harmless human parasite, uses also a wide variety of mammals host and hemipterous insects in its life cycle (Urdaneta-Morales & Tejero 1992). It has been postulated that immuno modulating mechanisms induced by T. rangeli may have relevance to protection against T. cruzi infection (Saldaña & Sousa 1996, Zúñiga et al 1997a).…”