Trypanosoma cruzi: clonal structure of parasite strains and the importance of principal clones

Trypanosoma cruzi-triatomine associations and the presence of mixed infections in single triatomine bugs in Paraná state, Brazil

“…These data are in agreement with recent findings that T. cruzi I and II circulate in north/northwest Paraná (Zalloum et al 2005). These results also indicate that the strains analyzed here are more closely associated with the sylvatic transmission cycle of T. cruzi in this region, as reported for isolates from the sylvatic cycle in the most diverse endemic areas of Brazil and other countries of southern South America (Fernandes et al 1997, Andrade 1999, Devera et al 2003.…”

Implications of genetic variability of Trypanosoma cruzi for the pathogenesis of Chagas disease

“…Thus, the biological types (biodemes) were correlated with the zymodemes (Z1, Z2, and Z3) described by Miles et al 22 , with type II biodeme corresponding to Z2 and type III to Z1 19 . The exception was type I, which presented a peculiar electrophoretic profile, not described previously 26 and was subsequently identified as Z2b.…”

“…Patients in endemic areas are probably infected by multiple contacts with different triatomines, and the latter in turn can feed on the blood of various infected individuals, thus leading to the formation of multiclonal populations in hosts and vectors 16 . Such populations differ in terms of their genetic and biological characteristics and their behavior in the vertebrate host 19 .…”

Variation in susceptibility to benznidazole in isolates derived from Trypanosoma cruzi parental strains

“…Studies using cloned or uncloned populations, reinforce the heterogeneity of the parasite and demonstrate that, in general, strains of T. cruzi are composed of subpopulations with distinct characteristics (Postan et al 1986, Finley & Dvorak 1987. Several authors have extensively investigated the correlation between T. cruzi genetic background and the different clinical forms of Chagas disease, as well as biological characteristics, such as virulence, pathogenicity and susceptibility to drugs (Revollo et al 1998, Andrade 1999. Filardi and Brener (1987) and Toledo et al (1997) been suggested as an important factor in explaining the low rates of cure detected in treated patients (Murta & Romanha 1998).…”