Probing population dynamics of Trypanosoma cruzi during progression of the chronic phase in chagasic patients.
Our research aimed to characterize the genetic profiles of 102 Trypanosoma cruzi isolates recently obtained from 44 chronic chagasic patients from different regions of the states of Minas Gerais and Goiás in Brazil. At least two isolates were obtained from each patient at different times in order to study the parasite population dynamics during disease progression in the chronic phase. The isolates were characterized molecularly by genotyping the 3' region of the 24S alpha rRNA, the mitochondrial cytochrome oxidase subunit 2 (COII) gene, and the intergenic region of the spliced leader intergenic region (SL-IR) gene. Seventy-seven isolates were analyzed for nine microsatellite loci. The data presented here show a strong correlation between the T. cruzi lineage II (T. cruzi II) and human infection in these regions of Brazil. Interestingly, isolates from two patients were initially characterized (by rRNA genotyping) as T. cruzi I and hybrid strains, but subsequent analyses of the COII and SL-IR genes confirmed that those isolates belonged to T. cruzi III and a hybrid group, respectively. Our results confirm the risk of misclassifying T. cruzi isolates on the basis of analysis of a single molecular marker. The microsatellite profiles showed that different isolates obtained from the same patient were genetically identical and monoclonal. Exceptions were observed for T. cruzi isolates from two patients who presented differences for the SCLE11 locus and also from two other patients who showed amplification of three peaks for a microsatellite locus (TcAAAT6), implying that they were multiclonal. On the basis of the findings of the studies described here, we were not able to establish a correlation between the clinical forms of Chagas' disease and the genetic profiles of the T. cruzi isolates.
Departamento de Parasitologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627 Caixa Postal 486, 31270-901, Belo Horizonte, Minas Gerais, Brazil.
Daniella Alchaar
DA
D'Avila
Andréa Mara
AM
Macedo
Helder Magno Silva
HM
Valadares
Eliane Dias
ED
Gontijo
Ana Maria
AM
de Castro
Carlos Renato
CR
Machado
Egler
E
Chiari
Lúcia Maria Cunha
LM
Galvão
D000328:Adult; D000368:Aged; D000818:Animals; D001938:Brazil; D014355:Chagas Disease / Q000469:parasitology*; D016000:Cluster Analysis; D021901:DNA, Intergenic / Q000235:genetics; D016054:DNA, Protozoan / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D008875:Middle Aged; D011110:Polymorphism, Genetic; D015800:Protozoan Proteins / Q000235:genetics; D016053:RNA, Protozoan / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics; D014349:Trypanosoma cruzi / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D055815:Young Adult
D021901:DNA, Intergenic; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D016053:RNA, Protozoan; D012335:RNA, Ribosomal; D003576:Electron Transport Complex IV