Trypanosoma cruzi: presence of the two major phylogenetic lineages and of several lesser discrete typing units (DTUs) in Chile and Paraguay

Barnabé, Christian; Neubauer, Katja; Solari, Aldo; Tibayrenc, Michel

doi:10.1016/s0001-706x(00)00183-2

Cited by 43 publications

(36 citation statements)

References 26 publications

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“…The restriction enzyme AclI distinguished between DTUs I/IIa/IIc and IIb/IId/IIe and was used for RFLP analysis of the amplified products ( Figure 1B). AclI digestion was applied to 15 additional strains previously classified into specific DTUs by RAPD and MLEE analysis (Barnabé et al 2001a; C. Barnabé and M. Tibayrenc, unpublished results). Strains from DTUs I, IIa, and IIc were not digested by AclI and were characterized by an 550-bp product, while strains representing DTUs IIb, IId, and IIe showed complete digestion, yielding 360-and 190-bp fragments.…”

Section: Resultsmentioning

confidence: 99%

“…However, the advantages of a heterozygous state are well documented and thus may persist in these strains, presenting an example of hybrid vigor. Indeed, these hybrids are isolated frequently from infected individuals throughout the southern geographical range of the disease (Barnabé et al 2000(Barnabé et al , 2001a. Heterozygous hybrids may possess a more successful phenotype that has adapted to, and conquered, a wide range of ecological niches as proposed elsewhere (Widmer et al 1987).…”

Section: Mosaic Sequences In Two Dtu Iie Strainsmentioning

confidence: 99%

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Two Hybridization Events Define the Population Structure of Trypanosoma cruzi

et al. 2005

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Genetic variation in Trypanosoma cruzi is likely a key determinant in transmission and pathogenesis of Chagas disease. We have examined nine loci as markers for the extant T. cruzi strains. Four distinct alleles were found for each locus, corresponding to the sequence classes present in the homozygous discrete typing units (DTUs) I, IIa, IIb, and IIc. The alleles in DTUs IIa and IIc showed a spectrum of polymorphism ranging from DTU I-like to DTU IIb-like, in addition to DTU-specific sequence variation. DTUs IId and IIe were indistinguishable, showing DTU homozygosity at one locus and heterozygosity with DTU IIb and IIc allelic sequences at eight loci. Recombination between the DTU IIb and IIc alleles is evidenced from mosaic polymorphisms. These data imply that two discrete hybridization events resulted in the formation of the current DTUs. We propose a model in which a fusion between ancestral DTU I and IIb strains gave rise to a heterozygous hybrid that homogenized its genome to become the homozygous progenitor of DTUs IIa and IIc. The second hybridization between DTU IIb and IIc strains that generated DTUs IId and IIe resulted in extensive heterozygosity with subsequent recombination of parental genotypes.

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Section: Resultsmentioning

confidence: 99%

Section: Mosaic Sequences In Two Dtu Iie Strainsmentioning

confidence: 99%

Two Hybridization Events Define the Population Structure of Trypanosoma cruzi

et al. 2005

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“…48 These results are similar to the those found in wild mammals, which suggested that these patterns can be detected in different hosts, and that the domestic and wild transmission cycles for T. cruzi are similar, as previously reported. 52 …”

Section: Discussionmentioning

confidence: 99%

Coexistence of Trypanosoma cruzi Genotypes in Wild and Periodomestic Mammals in Chile

et al. 2007

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Abstract. Epidemiologic evidence suggests a preferential association of Trypanosoma cruzi genotypes TCI and TCII with marsupials and placental mammals, respectively. We identify T. cruzi genotypes from 117 infected mammals. Minicircle DNA amplified by polymerase chain reaction and hybridization with a panel of four specific probes showed frequencies for the T. cruzi genotypes TCI, TCIIb, TCIId, and TCIIe of 38%, 41%, 26%, and 9%, respectively, in wild mammals. In peridomestic mammals, frequencies for the same clones were 29%, 33%, 43%, and 14%, respectively. As a whole, mixed infections are found in more than 31% of the cases, which indicates the coexistence of multiclonal strains circulating in nature, and the absence of specific associations between T. cruzi genotypes and reservoir hosts, including marsupials. The direct characterization of parasite genotypes emphasizes the importance of obtaining unbiased epidemiologic information from parasite-endemic areas. Results are discussed in the context of competition or facilitation of T. cruzi genotypes within hosts.

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“…16 Using PCR-RFLP, Rozas and others reported TcI, TcIIb (currently TcII), TcIIa or TcIIc (currently TcIII and TcIV), and TcIId or TcIIe (TcV and TcVI) in single and mixed infections of mammals, Mepraia spinolai and humans from the Coquimbo Region, the hyperendemic area of Chile. 17 More recently, the presence of TcIII was documented in Triatoma infestans from Chile by using three microsatellite markers, with TcI, a hybrid (TcV + TcVI), and unknown lineages.…”

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Differential Pattern of Infection of Sylvatic Nymphs and Domiciliary Adults of Triatoma infestans with Trypanosoma cruzi Genotypes in Chile

Bacigalupo¹,

Segovia²,

García³

et al. 2012

The American Society of Tropical Medicine and Hygiene

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Abstract. In Chile, the main vector of Chagas disease, Triatoma infestans, is under control after insecticide spraying. However, it has been found colonizing wild habitats. This study evaluated Trypanosoma cruzi infection of sylvatic and domiciliary T. infestans and identified their parasite genotypes. The sample studied was composed mainly of T. infestans sylvatic nymphs and domiciliary adults from a semi-urban area with human dwellings under vector control surveillance. Results showed prevalences of 57.7% in nymphs and 68.6% in adults. Hybridization tests showed a major T. cruzi lineage (TcI) circulating in sylvatic (93.3%) and domiciliary (100%) T. infestans. TcII, TcV, and TcVI were also detected, mainly in nymphs, suggesting differential adaptation of T. cruzi lineages among instars. We also discuss the origin of domiciliary individuals of T. infestans and the risk of human infection by triatomines of sylvatic foci that invade houses despite vector control programs.

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Trypanosoma cruzi: presence of the two major phylogenetic lineages and of several lesser discrete typing units (DTUs) in Chile and Paraguay

Cited by 43 publications

References 26 publications

Two Hybridization Events Define the Population Structure of Trypanosoma cruzi

Two Hybridization Events Define the Population Structure of Trypanosoma cruzi

Coexistence of Trypanosoma cruzi Genotypes in Wild and Periodomestic Mammals in Chile

Differential Pattern of Infection of Sylvatic Nymphs and Domiciliary Adults of Triatoma infestans with Trypanosoma cruzi Genotypes in Chile

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