The sylvatic cycle of Trypanosoma cruzi: a still unsolved puzzle

Jansen, Ana Maria; Pinho, Ana Paula; Lisboa, Cristiane Varella; Cupolillo, Elisa; Mangia, Regina Helena Riccioppo; Fernandes, Octávio

doi:10.1590/s0074-02761999000700030

Cited by 40 publications

(24 citation statements)

References 9 publications

(6 reference statements)

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“…Recent studies have shown that in a nonendemic area of the Brazilian Atlantic coastal rainforest 50% of the triatomine vectors and of the marsupials Didelphis marsupialis and Philander opossum [7] as well as 52% of the golden lion tamarins and several other species of New World primates [8] were naturally infected with T. cruzi.…”

Section: Introductionmentioning

confidence: 99%

Ancestral Genomes, Sex, and the Population Structure of Trypanosoma cruzi

et al. 2006

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Acquisition of detailed knowledge of the structure and evolution of Trypanosoma cruzi populations is essential for control of Chagas disease. We profiled 75 strains of the parasite with five nuclear microsatellite loci, 24Sα RNA genes, and sequence polymorphisms in the mitochondrial cytochrome oxidase subunit II gene. We also used sequences available in GenBank for the mitochondrial genes cytochrome B and NADH dehydrogenase subunit 1. A multidimensional scaling plot (MDS) based in microsatellite data divided the parasites into four clusters corresponding to T. cruzi I (MDS-cluster A), T. cruzi II (MDS-cluster C), a third group of T. cruzi strains (MDS-cluster B), and hybrid strains (MDS-cluster BH). The first two clusters matched respectively mitochondrial clades A and C, while the other two belonged to mitochondrial clade B. The 24Sα rDNA and microsatellite profiling data were combined into multilocus genotypes that were analyzed by the haplotype reconstruction program PHASE. We identified 141 haplotypes that were clearly distributed into three haplogroups (X, Y, and Z). All strains belonging to T. cruzi I (MDS-cluster A) were Z/Z, the T. cruzi II strains (MDS-cluster C) were Y/Y, and those belonging to MDS-cluster B (unclassified T. cruzi) had X/X haplogroup genotypes. The strains grouped in the MDS-cluster BH were X/Y, confirming their hybrid character. Based on these results we propose the following minimal scenario for T. cruzi evolution. In a distant past there were at a minimum three ancestral lineages that we may call, respectively, T. cruzi I, T. cruzi II, and T. cruzi III. At least two hybridization events involving T. cruzi II and T. cruzi III produced evolutionarily viable progeny. In both events, the mitochondrial recipient (as identified by the mitochondrial clade of the hybrid strains) was T. cruzi II and the mitochondrial donor was T. cruzi III.

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Section: Introductionmentioning

confidence: 99%

Ancestral Genomes, Sex, and the Population Structure of Trypanosoma cruzi

et al. 2006

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“…Studies showed that mammals and vectors in the same region, and even in the same forest fragment, may be involved in distinct transmission cycles with distinct host competence (Pinho et al 2000 ;Lisboa et al 2004). This shows that the dispersal of T. cruzi in the wild occurs in complex transmission cycles ruled by factors still unknown (Jansen et al 1999). In addition, habitat fragmentation or deforestation processes, by decreasing the biodiversity and/or favouring the maintenance of more generalist and tolerant species (Castro and Fernandez, 2004 ;Gillespie et al 2005), can explain the re-emergence of Chagas disease in Brazil.…”

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Effects of habitat fragmentation on wild mammal infection by Trypanosoma cruzi

Vaz

D’Andrea

Jansen³

2007

Parasitology

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Expansion of human activities frequently results in habitat fragmentation, a phenomenon that has been widely recognized in the last decades as one of the major threats to world's biodiversity. The transformation of a continuous forest into a fragmented area results in a hyper-dynamic landscape with unpredictable consequences to overall ecosystem health. The effect of the fragmentation process on Trypanosoma cruzi infection among small wild mammals was studied in an Atlantic Rain Forest landscape. Comparing continous forest to fragmented habitat, marsupials were less abundant than rodents in the continuous landscape. An overall decrease in small wild mammal richness was observed in the smaller fragments. An anti-T. cruzi seroprevalence of 18% (82/440) was deteced by immunofluorescence assay. Moreover, this seroprevalence was higher in the fragmented habitat than in the continuous forest. According to the collected data, 3 main factors seem to modulate infection by T. cruzi in small wild mammals: (i) habitat fragmentation; (ii) biodiversity loss; (iii) increase of marsupial abundance in mammal communities. Furthermore, an extremely mild controlled infection by T. cruzi was detected since no patent parasitaemia could be detected in fresh blood samples, and no parasites were isolated by haemoculture.

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“…Particular phylogenetic groups of T. cruzi seem to preferentially infect certain reservoir hosts. There is evidence suggesting that TcII (but not TcI) causes severe, parasitemic disease to rodents, while D. marsupialis eliminate TcII and retain TcI 24 . Field studies show that TcI is often associated with marsupials (mainly Didelphis spp.…”

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“…However, enzootic cycles involving TcII and marsupials (Philander frenata) have also been described, even in areas where TcI was isolated from sympatric Didelphis 33 . The relationships among wild cycles and between these and domestic ones are extremely complex, but a common trait is that opossums seem to play a key role in transmission dynamics 13,15,24 .…”

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Enzootic transmission of Trypanosoma cruzi and T. rangeli in the Federal District of Brazil

Gurgel-Gonçalves

Ramalho

Duarte

et al. 2004

Rev. Inst. Med. trop. S. Paulo

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SUMMARYThe Federal District of Brazil (DF) lies within the Cerrado biome, where open shrubland (savannas) is interspersed with riverside gallery forests and permanent swamps (veredas). Trypanosoma cruzi-infected native triatomines occur in the area, but the enzootic transmission of trypanosomatids remains poorly characterized. A parasitological survey involving sylvatic triatomines (166 Rhodnius neglectus collected from Mauritia flexuosa palms) and small mammals (98 marsupials and 70 rodents, totaling 18 species) was conducted in 18 sites (mainly gallery forests and veredas) of the DF. Parasites were isolated, morphologically identified, and characterized by PCR of nuclear (mini-exon gene) and kinetoplast DNA (kDNA). Six R. neglectus, seven Didelphis albiventris and one Akodon cursor were infected by trypanosomes; wild reservoir infection is documented for the first time in the DF. kDNA PCR detected T. cruzi in five R. neglectus and mini-exon gene PCR revealed T. cruzi I in isolates from D. albiventris. Parasites infecting one bug yielded T. rangeli KP1+ kDNA amplicons. In spite of the occurrence of T. cruzi-infected D. albiventris (an important wild and peridomestic reservoir) and R. neglectus (a secondary vector displaying synanthropic behavior), a low-risk of human Chagas disease transmission could be expected in the DF, considering the low prevalence infection recorded in this work. The detection of T. rangeli KP1+ associated with R. neglectus in the DF widens the known range of this parasite in Brazil and reinforces the hypothesis of adaptation of T. rangeli populations (KP1+ and KP1-) to distinct evolutionary Rhodnius lineages.

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The sylvatic cycle of Trypanosoma cruzi: a still unsolved puzzle

Cited by 40 publications

References 9 publications

Ancestral Genomes, Sex, and the Population Structure of Trypanosoma cruzi

Ancestral Genomes, Sex, and the Population Structure of Trypanosoma cruzi

Effects of habitat fragmentation on wild mammal infection by Trypanosoma cruzi

Enzootic transmission of Trypanosoma cruzi and T. rangeli in the Federal District of Brazil

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