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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

Sampling sites of wild populations of Triatoma infestans in Bolivia.The sites were numbered from 1 to 36, Bolivian department names are indicated, for the DTU T. cruzi results see in Table 1.
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pntd-0001650-g001: Sampling sites of wild populations of Triatoma infestans in Bolivia.The sites were numbered from 1 to 36, Bolivian department names are indicated, for the DTU T. cruzi results see in Table 1.

Mentions: The triatomines were sampled in sylvatic environments from April to November 2009 (Figure 1). Collections were carried out using mice-baited adhesive traps [40] in different ecotopes such as under bush and bromeliads, rocks, burrows, hollow trees, and stone walls. The bugs were transported alive to the laboratory for species confirmation using morphological taxonomic keys [41]. Table 1 summarizes the geographical and ecotope origin of the collected T. infestans according to the ecoregions defined in [42]. Briefly, the majority of the bugs were collected in Andean valleys where sylvatic foci have been previously described [21], [24] and the others were collected from new foci in the Bolivian Chaco where the “dark morph” type of T. infestans was discovered [22], [26]. Before dissection, feces from each bug were examined for the presence of trypanosomatid by direct microscopic observation at ×400 magnification (mo). Bugs were then dissected under a safety hood, and the digestive tracts stored at −20°C.


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)

Sampling sites of wild populations of Triatoma infestans in Bolivia.The sites were numbered from 1 to 36, Bolivian department names are indicated, for the DTU T. cruzi results see in Table 1.
© Copyright Policy
Related In: Results  -  Collection

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

pntd-0001650-g001: Sampling sites of wild populations of Triatoma infestans in Bolivia.The sites were numbered from 1 to 36, Bolivian department names are indicated, for the DTU T. cruzi results see in Table 1.
Mentions: The triatomines were sampled in sylvatic environments from April to November 2009 (Figure 1). Collections were carried out using mice-baited adhesive traps [40] in different ecotopes such as under bush and bromeliads, rocks, burrows, hollow trees, and stone walls. The bugs were transported alive to the laboratory for species confirmation using morphological taxonomic keys [41]. Table 1 summarizes the geographical and ecotope origin of the collected T. infestans according to the ecoregions defined in [42]. Briefly, the majority of the bugs were collected in Andean valleys where sylvatic foci have been previously described [21], [24] and the others were collected from new foci in the Bolivian Chaco where the “dark morph” type of T. infestans was discovered [22], [26]. Before dissection, feces from each bug were examined for the presence of trypanosomatid by direct microscopic observation at ×400 magnification (mo). Bugs were then dissected under a safety hood, and the digestive tracts stored at −20°C.

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