IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Rocha, F.L. | |
| A rede tr¢fica e o papel dos carn¡voros silvestres nos ciclos de transmissÆo de _Trypanosoma cruzi_ | |
| 2013 Full Book | |
Little is known on the _Trypanosoma cruzi_ trasmission in the different trophic levels of the food web and on the role played by Neotropical wild carnivores, the mammalian group target of this study, in the transmission cicles of this parasite. _T. cruzi_, the etiologic agent of Chagas disease, is a multihost parasite immersed in complex transmission networks that include hundreds of mammalian species and dozens of triatomines species, the insect vectors. The new epidemiological scenario, expressed by the growing number of human cases due to _t. cruzi_ oral infection, demonstrate that numerous aspects of Chagas disease epidemiology still remain unclear. The primarly enzootic nature of this parasitosis emphasize the importance of looking at the sylvatic cycle to examine the role of the different mammalian species in the maintenance of the parasite in order to understand this new scenario. Therefore, we examined six mammalian orders, domestic dogs and feral pigs for _T. cruzi_ infection and its distinct genotypres, through serologic, parasitological and molecular tests, during a seven-year follow-up in the Pantanal, Mato Grosso do Sul State, Brazil. We demonstrated that the reservoir system in the Pantanal includes host species that occupy all habitat types and forest strata, constituting a transmission network involving generalist and specialist mammalian species that are linked through a robust food-eb connection. In this system, the coati (_Nasua nasua_) was considered the main_ T. cruzi_ reservoir, and demonstrated potential to act as a bioacumulator and disperser of all the _T. cruzi_ genotypes detected in the region TcI, TcII and TcIII/IV. The extension of our studies to the Serra da Canastra National Park (SCNP) Minas Gerais State, and to the Araguari/cumari regions (Minas Gerais/Goias States) provided evidence that the participation of wild carnivores in the _T. cruzi_ transmission cycles was not a punctual finding, given that the seven carnivore species examined in the three study sites were infected by _T. cruzi_. Infectivity potential (expressed by positive hemoculture) was demonstrated in a felid from the SCNP, the ocelot_ _(_Leopardus pardalis_), and in two procyonid species from the Pantanal, the coati and the raccoon (_Procyon cancrivorus_). In the SCNP, domestic dogs demonstrated to be good sentinels for _T. cruzi_ transmission areas and the distinct genotypes circulating in the region, TcI and TcII. Additionally, we provided a comprehensive analysis of infection patterns among distinct carnivore species, by assembling our data with _T. cruzi_ infection on South America carnivores' literature records. Twelve out of twenty-one Neotropical carnivores evaluated species were described to be infected by _T. cruzi_, besides other three species found infected in the present study: the ocelot, the puma (_Puma concolor_) and the maned wolf (_Chrysocyon brachyurus_). Species diet was associated with _T. cruzi_ infection rates: the higher the proportion of invertebrates in species diet, the greater _T. cruzi_ infection rate. |
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