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Genetic characterization of Trypanosoma cruzi DTUs in wild Triatoma infestans from Bolivia: predominance of TcI.

Brenière SF, Aliaga C, Waleckx E, Buitrago R, Salas R, Barnabé C, Tibayrenc M, Noireau F - PLoS Negl Trop Dis (2012)

Bottom Line: Of 333 wild Triatoma infestans specimens collected from north to south of a Chagas disease endemic area in Bolivia, we characterized 234 stocks of Trypanosoma cruzi using mini-exon multiplex PCR (MMPCR) and sequencing the glucose phosphate isomerase (Gpi) gene.In the lowlands (Bolivian Chaco), 17 "dark morph" T. infestans were analyzed.By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles.

View Article: PubMed Central - PubMed

Affiliation: MIVEGEC (Université de Montpellier 1 et 2, CNRS 5290, IRD 224), Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour développement, Representation in Bolivia, La Paz, Bolivia. Frederique.Breniere@ird.fr

ABSTRACT

Background: The current persistence of Triatoma infestans (one of the main vectors of Chagas disease) in some domestic areas could be related to re-colonization by wild populations which are increasingly reported. However, the infection rate and the genetic characterization of the Trypanosoma cruzi strains infecting these populations are very limited.

Methodology/principal findings: Of 333 wild Triatoma infestans specimens collected from north to south of a Chagas disease endemic area in Bolivia, we characterized 234 stocks of Trypanosoma cruzi using mini-exon multiplex PCR (MMPCR) and sequencing the glucose phosphate isomerase (Gpi) gene. Of the six genetic lineages ("discrete typing units"; DTU) (TcI-VI) presently recognized in T. cruzi, TcI (99.1%) was overdominant on TcIII (0.9%) in wild Andean T. infestans, which presented a 71.7% infection rate as evaluated by microscopy. In the lowlands (Bolivian Chaco), 17 "dark morph" T. infestans were analyzed. None of them were positive for parasites after microscopic examination, although one TcI stock and one TcII stock were identified using MMPCR and sequencing.

Conclusions/significance: By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles.

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Related in: MedlinePlus

Illustrating electrophoresis of MMPCR products.Ez-vision stained 3% agarose gel containing MMPCR products obtained from DNA extracts of reference strains and current digestive tracts of T. infestans. Lane 1, sample Tor05; lane 2, PCR negative sample; lane 3, the molecular weight marker Smart Ladder (Eurogentec, Angers, France); lane 4–6, reference strains (M6241cl6, P209cl1 and MNcl2 respectively); lane 7–8, sample Char09 (two independent PCR); lane 9, sample Lur112. See Table 2 for DTUs information.
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pntd-0001650-g002: Illustrating electrophoresis of MMPCR products.Ez-vision stained 3% agarose gel containing MMPCR products obtained from DNA extracts of reference strains and current digestive tracts of T. infestans. Lane 1, sample Tor05; lane 2, PCR negative sample; lane 3, the molecular weight marker Smart Ladder (Eurogentec, Angers, France); lane 4–6, reference strains (M6241cl6, P209cl1 and MNcl2 respectively); lane 7–8, sample Char09 (two independent PCR); lane 9, sample Lur112. See Table 2 for DTUs information.

Mentions: A total of 333 DNA samples from digestive tracts of wild T. infestans were processed in MMPCR for DTU identification. Among them 20.1% were adults of both sexes, 64.1% 4th and 5th instar nymphs, and 15.8% 2nd and 3rd instar nymphs. Before dissection, the bug feces were examined (85.0% of the total sample) using microscopy. The parasite infection rate was 71.7% in Andean specimens while no positive insect was found among the 17 specimens from Chaco (GC ecoregion). The accordance between microscopic observation and MMPCR was 82%, with 93.1% of positive MMPCR when mo was positive and 17,5% when mo was negative. The identification of the three DTUs was assessed by determining the molecular weight of the MMPCR products for each sample (Table 1, Figure 2). The results showed that the large majority (98.3%) of the 234 wild T. infestans specimens were infected by TcI (PCR products of 200 bp). Only one sample from an adult T. infestans (“dark morph” type) collected at site 32 (GC ecoregion) gave a 250 bp MMPCR product corresponding to TcII, TcV, or TcVI. Three other samples (sites 23, 25, and 29) gave a 150 bp MMPCR products corresponding to either TcIII or TcIV. The MMPCR product of the specimen of the latter group captured at site 29 was sequenced and the DNA fragment (64 bp) matched the TcIII reference stock named M5631 (accession No AF050521.1 and AY367126.1, 98% identity).


Genetic characterization of Trypanosoma cruzi DTUs in wild Triatoma infestans from Bolivia: predominance of TcI.

Brenière SF, Aliaga C, Waleckx E, Buitrago R, Salas R, Barnabé C, Tibayrenc M, Noireau F - PLoS Negl Trop Dis (2012)

Illustrating electrophoresis of MMPCR products.Ez-vision stained 3% agarose gel containing MMPCR products obtained from DNA extracts of reference strains and current digestive tracts of T. infestans. Lane 1, sample Tor05; lane 2, PCR negative sample; lane 3, the molecular weight marker Smart Ladder (Eurogentec, Angers, France); lane 4–6, reference strains (M6241cl6, P209cl1 and MNcl2 respectively); lane 7–8, sample Char09 (two independent PCR); lane 9, sample Lur112. See Table 2 for DTUs information.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368956&req=5

pntd-0001650-g002: Illustrating electrophoresis of MMPCR products.Ez-vision stained 3% agarose gel containing MMPCR products obtained from DNA extracts of reference strains and current digestive tracts of T. infestans. Lane 1, sample Tor05; lane 2, PCR negative sample; lane 3, the molecular weight marker Smart Ladder (Eurogentec, Angers, France); lane 4–6, reference strains (M6241cl6, P209cl1 and MNcl2 respectively); lane 7–8, sample Char09 (two independent PCR); lane 9, sample Lur112. See Table 2 for DTUs information.
Mentions: A total of 333 DNA samples from digestive tracts of wild T. infestans were processed in MMPCR for DTU identification. Among them 20.1% were adults of both sexes, 64.1% 4th and 5th instar nymphs, and 15.8% 2nd and 3rd instar nymphs. Before dissection, the bug feces were examined (85.0% of the total sample) using microscopy. The parasite infection rate was 71.7% in Andean specimens while no positive insect was found among the 17 specimens from Chaco (GC ecoregion). The accordance between microscopic observation and MMPCR was 82%, with 93.1% of positive MMPCR when mo was positive and 17,5% when mo was negative. The identification of the three DTUs was assessed by determining the molecular weight of the MMPCR products for each sample (Table 1, Figure 2). The results showed that the large majority (98.3%) of the 234 wild T. infestans specimens were infected by TcI (PCR products of 200 bp). Only one sample from an adult T. infestans (“dark morph” type) collected at site 32 (GC ecoregion) gave a 250 bp MMPCR product corresponding to TcII, TcV, or TcVI. Three other samples (sites 23, 25, and 29) gave a 150 bp MMPCR products corresponding to either TcIII or TcIV. The MMPCR product of the specimen of the latter group captured at site 29 was sequenced and the DNA fragment (64 bp) matched the TcIII reference stock named M5631 (accession No AF050521.1 and AY367126.1, 98% identity).

Bottom Line: Of 333 wild Triatoma infestans specimens collected from north to south of a Chagas disease endemic area in Bolivia, we characterized 234 stocks of Trypanosoma cruzi using mini-exon multiplex PCR (MMPCR) and sequencing the glucose phosphate isomerase (Gpi) gene.In the lowlands (Bolivian Chaco), 17 "dark morph" T. infestans were analyzed.By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles.

View Article: PubMed Central - PubMed

Affiliation: MIVEGEC (Université de Montpellier 1 et 2, CNRS 5290, IRD 224), Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle, Institut de Recherche pour développement, Representation in Bolivia, La Paz, Bolivia. Frederique.Breniere@ird.fr

ABSTRACT

Background: The current persistence of Triatoma infestans (one of the main vectors of Chagas disease) in some domestic areas could be related to re-colonization by wild populations which are increasingly reported. However, the infection rate and the genetic characterization of the Trypanosoma cruzi strains infecting these populations are very limited.

Methodology/principal findings: Of 333 wild Triatoma infestans specimens collected from north to south of a Chagas disease endemic area in Bolivia, we characterized 234 stocks of Trypanosoma cruzi using mini-exon multiplex PCR (MMPCR) and sequencing the glucose phosphate isomerase (Gpi) gene. Of the six genetic lineages ("discrete typing units"; DTU) (TcI-VI) presently recognized in T. cruzi, TcI (99.1%) was overdominant on TcIII (0.9%) in wild Andean T. infestans, which presented a 71.7% infection rate as evaluated by microscopy. In the lowlands (Bolivian Chaco), 17 "dark morph" T. infestans were analyzed. None of them were positive for parasites after microscopic examination, although one TcI stock and one TcII stock were identified using MMPCR and sequencing.

Conclusions/significance: By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles.

Show MeSH
Related in: MedlinePlus