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Previous issue date: 2013-11-21 === Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil === Diversos surtos epidêmicos causados por agentes patogênicos provocaram severo declínio em populações de carnívoros selvagens nas últimas décadas. Além desse impacto às populações silvestres, há a preocupação de transmissão de alguns desses agentes à população humana e animais domésticos. De fato, as alterações ambientais têm provocado mudanças na relação patógeno-hospedeiro. Desta forma, o monitoramento da saúde de animais silvestres é importante componente no estabelecimento de programas de controle e erradicação de doenças e na elaboração de políticas de saúde pública e animal e de manejo e conservação de espécies selvagens. Considerando o papel dos mamíferos da ordem Carnívora na cadeia trófica, estes podem ser usados como sentilas sendo alvos estratégicos em programas de vigilância para detecção de patógenos
Neste artigo serão revisados estudos de caso dos principais patógenos que acometem mamíferos selvagens, com ênfase nas espécies da fauna brasileira. Os métodos laboratoriais utilizados nos estudos de exposição dos carnívoros brasileiros a patógenos serão discutidos e considerações sobre estratégias para minimizar seus impactos sobre a fauna silvestre, bem como os possíveis métodos para controle de patógenos causadores de zoonoses em carnívoros === Little is known on the
Trypanosoma cruzi
transmission 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 cycles 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 genotypes, 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-web 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
). Each species demonstrated a different potential to maintain and disperse
T. cruzi
, according their ecological characteristics and peculiarities of the different study areas.
Species diet was associated with
T. cruzi
infection rates: the higher the proportion of invertebrates
in species diet, the greater
T. cruzi
infection rate. Musteloidea species consistently exhibit high
parasitemias in different studies, which indicate their high infectivity potential. Mesocarnivores that
feed on both invertebrates and mammals, including the coati, a host that can be bioaccumulator of
T. cruzi
genotypes, seem to take place at the top of
T. cruzi
transmission chain; therefore, they may
have a huge impact on the transmission cycles of this parasite.
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