Biodemes and zymodemes of Trypanosoma cruzi strains: correlations with clinical data and experimental pathology

Abstract

With the objective of establishing biological and biochemical characteristics of a significant number of Trypanosoma cruzi strains from different geographical areas, 138 strains isolated from naturally infected humans, triatomine or vertebrate hosts were studied; 120 were isolated from different areas of Brazil and 18 from other South and Central American countries. Inocula from triatomine or culture forms were injected into suckling Swiss mice, followed by passages into mice 10 to 12 g. Biological characters and histopathological study permitted the inclusion of the strains into three Types or biodemes: I, II, III. Isoenzymic analysis confirmed a correspondence between the biodemes and zymodemes : Type I and Z2b, Type II and Z2, Type III and Z1. Results showed the ubiquitary distribution of the several types of strains. The predominance of the same Type and zymodeme in one geographical area was confirmed : Type II strains among the human cases from eastern Bahia and east of Goiás; Type III strains from humans of north Brazil and Central America and from silvatic vectors or vertebrates from other geographical areas. The biological types of strains correlate with different histopathological lesions considering cardiac involvement and neuronal lesions. These findings suggest that the biological behavior together with isoenzymes patterns and pathological pictures in the vertebrate host can be an important tool for establishing correlations between strains behavior and clinico-pathological manifestations of Chagas' disease in different geographical areas.

Response to chemotherapy with benznidazole of clones isolated from the 21SF strain of Trypanosoma cruzi (biodeme Type II, Trypanosoma cruzi II)

“…A wide individual variability of the cure rates between them has been detected. These results differ from those obtained for the biodeme Type I strains (Z2b), that showed high susceptibility and for the biodeme Type III strains (T. cruzi I), with a high degree of resistance 2 .…”

“…A variability in the susceptibility between the strains of biodeme Type II has also been observed 2 and, considering the mean cure rates obtained by the evaluation of 15 strains of the referred biodeme, they were classified as presenting medium to high susceptibility. A wide individual variability of the cure rates between them has been detected.…”

“…Strains of Trypanosoma cruzi characterized as different Types or biodemes 1 3 have exhibited well-marked differences in their response to chemotherapy, either with nifurtimox or benznidazole 2 . A variability in the susceptibility between the strains of biodeme Type II has also been observed 2 and, considering the mean cure rates obtained by the evaluation of 15 strains of the referred biodeme, they were classified as presenting medium to high susceptibility.…”

Expanding the knowledge of the chemical structure of glycoconjugates from Trypanosoma cruzi TcI genotype. Contribution to taxonomic studies

“…cruzi strains present a large biochemical and genetic variability (Gomes et al 2003, Macedo et al 2004), leading to astounding differences in terms of morphology, tissue tropism, virulence and drug susceptibility (de Diego et al 1998, Andrade andMagalhães 1997). Such different characteristics stimulated a search for new molecular markers that allow the correlation between protozoan genotype and clinical manifestations, leading to a more complete diagnosis and better treatment protocols.…”

Análisis por LSSP-PCR de la variabilidad genética de Trypanosoma cruzi en sangre y órganos de ratones.

“…Así, mientras las manifestaciones gastrointestinales son raras en Centroamérica, México, Colombia y Venezuela (12), en Brasil, estas manifestaciones tienen mayor incidencia con o sin patología cardiaca asociada (13). Sin embargo, en estudios recientes se ha podido establecer que las poblaciones multiclonales que infectan un individuo, tienen clones con tropismo específico a diferentes tejidos y es exactamente la distribución de estos clones lo que puede influir o determinar el curso clínico de cada paciente (14). También se ha observado que los clones predominantes en las cepas pueden ser los responsables del tropismo preferencial hacia órganos y tejidos específicos, y esto podría contribuir a diferentes patrones de manifestación clínico-patológica en un área geográfica determinada (15), lo que se conoce como el modelo histotrópico clonal de la enfermedad de Chagas (16).…”