Reflections on the population dynamics of Trypanosoma cruzi: heterogeneity versus plasticity

Pacheco, Raquel S.; Brito, Celia Maria Marques

doi:10.1590/s0074-02761999000700029

Cited by 10 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In recent years the committee of the "International symposium on the advances in knowledge of Chagas disease 90 years after its discovery" [5] decided to classify T. cruzi isolates in two groups: T. cruzi I associated with the sylvatic cycle and T. cruzi II with the domestic cycle. This intra-specific heterogeneity has also been demonstrated by different genotypic and phenotypic markers, confirming the multiclonal structure of T. cruzi populations [6-8], probably having important clinical and epidemiological impact. As a consequence people living in endemic areas are frequently exposed to independent multiple infection, constantly leading to an accumulation of genetic endogenous variability [9,10] that contributes to the polyclonality of primary T. cruzi isolates.…”

Section: Introductionsupporting

confidence: 57%

Untitled

Brito

Pires

Pacheco

2003

Kinetoplastid Biol Dis

Self Cite

View full text Add to dashboard Cite

Background: Recently new aspects of the immunopathology of Chagas disease have been described in patients infected with HIV and unusual clinical manifestations such as cutaneous lesions, involvement of central nervous system and/or serious cardiac lesions related to the reactivation of the parasite have been reported. Two uncloned Trypanosoma cruzi strains previously isolated from chronic chagasic patients with HIV co-infection were studied in order to evaluate the impact of the immunosuppression on the genetic diversity of the parasite.

show abstract

Section: Introductionsupporting

confidence: 57%

Untitled

Brito

Pires

Pacheco

2003

Kinetoplastid Biol Dis

Self Cite

View full text Add to dashboard Cite

show abstract

“…In such specific cases individuals would be exposed to distinct selective pressures, to the polyclonality of the initial inoculum and also to multiple independent infections. If the biological entity that evolves is the clonal lineage [18], one can imagine different clones being reshuffled and propagated in the natural circulating population, sharing different factors of virulence or competing for selective advantages such as distinct growth rates and differential tropisms [23,24]. …”

Section: Discussionmentioning

confidence: 99%

American tegumentary leishmaniasis caused by Leishmania (Viannia) braziliensis: assessment of parasite genetic variability at intra- and inter-patient levels

et al. 2013

Self Cite

View full text Add to dashboard Cite

BackgroundThe genetic variability of Leishmania (Viannia) braziliensis was assessed at intra and interpatient levels of individuals with different clinical manifestations of American tegumentary leishmaniasis (ATL).MethodsFifty-two samples, of which 13 originated from cutaneous lesions and 39 from mucosal lesions, provided by 35 patients, were examined by low-stringency single-specific-primer PCR (LSSP-PCR) and phenetic analysis. Genetic variability of L. (V.) braziliensis, in kinetoplast DNA (kDNA) signatures, was compared both from different patients and from different lesions of the same patient. Phenetic analysis was performed to evaluate the degree of heterogeneity of the kDNA minicircles. In order to evaluate inter and intrapatient L. (V.) braziliensis genetic variability, the percentage of shared bands and analysis of the coefficients of similarity were analyzed.ResultsDifferent genetic profiles, representing kDNA signatures of the parasite, were obtained by LSSP-PCR analysis of each sample. Phenetic analysis grouped genetic profiles of different levels of differentiation from more similar to most divergent. The percentage of shared bands at the inter and intrapatient levels was 77% and 89%, respectively. Comparison of the average inter and intrapatient coefficients of similarity and their standard deviations were statistically significant (p < 0.001).ConclusionGenetic variability at the intrapatient level was less pronounced than that between different patients. A conceptual model was proposed to better understand the complexity at both levels.

show abstract

“…Pacheco and Brito (1999) studying parasite population in mice revealed evidence that polymorphism in minicircles sequences can emerge during infection with a single clone of T. cruzi. MacDaniel and Dvorak (1993) also showed that under stress conditions, or selective pressures, chromossomes and minicircles shown evidences of genetic plasticity (Lanzer et al 1994).…”

Section: Discussionmentioning

confidence: 99%