M. leprae.
Although D. novemcinctus is frequently described as one of the
main reservoirs for M. leprae, E. sexcinctus was also described
naturally infected for the first time in an endemic area for human
Hanseniasis, in Ceará state, northeast of Brazil (Frota et al., 2012).
Regardless of the methods applied, M. leprae was not detected in
any of the armadillo samples in this study. The results are in
accordance with previous studies in the region (Pedrini et al., 2010).
Using molecular analysis (PCR) the authors investigated 22 E.
sexcinctus , and other three species of armadillo (D.
novemcinctus , n = 18; C. unicinctus , n = 2; C. tatouay , n
= 2) from two different regions, in the southeast and in the central
states of Brazil, including Mato Grosso do Sul state, and all
individuals tested negative. According to Truman et al. (2008), negative
results might also be related to a non-endemic area for M.
leprae , as is the case of the herein investigated areas.
Soil is the probable main habitat for P. brasiliensis. Humans
were considered the only hosts of P. brasiliensis for a long
time, until the description of naturally infected armadillos in endemic
areas of Brazil (Bagagli et al., 2008). Then, the use of molecular
analysis enabled the diagnosis of P. brasiliensis in other mammal
species, like rodents (Cavia aperea and Sphiggurus
spinosus ) and carnivores (Procyon cancrivorus andGallictis vittata ), which are also considered as new hosts for
this fungus (Costa et al., 1995; Richini-Pereira et al., 2008; Bagagli
and Bosco, 2008).
There is little comprehension about the real meaning of P.
brasiliensis infection in armadillos, both for the fungus
eco-epidemiology and for the animal health, and its possible impacts in
wildlife and conservation. The prevalence of P. brasiliensisinfection in nine-banded armadillos is very high, especially in endemic
regions for this parasite where the fungus was isolated in 75-100% of
the studied armadillos (Bagagli and Bosco, 2008). Both armadillos andParacoccidioides species have originated and evolved in South
America over the last millions of years, with a high likelihood to
stablish biological relationships that might be positive for the fungus
dissemination while probably neutral for the armadillos. However, we
cannot rule out the possibility that this association is actually more
recent (e.g. in the last 500 years), as the result of human interference
in nature, in a similar manner to the relationship suggested forM. leprae and the nine-banded armadillo (Bagagli et al., 2008;
Truman et al., 2011).
As seen for for M. leprae , D. novemcinctus is the most
studied species, but P. brasiliensis could also be isolated inCabassous centralis and molecularly detected in D.
septemcinctus and D. hybridus (Bagagli and Simões, 2005;
Richini-Pereira et al., 2009; Corredor et al., 2005). Although studies
performed by several authors presented similar prevalence rates
(75-100%; Fernandes et al., 2004; Silva-Vergara et al., 2000; Bagagli
et al., 2008; Richini-Pereira et al., 2009), this is the first study
describing armadillos infected by P. brasiliensis in a
non-endemic area and the species E. sexcinctus infected by this
fungus in the Cerrado biome in Mato Grosso do Sul. These results also
highlight the importance of the relationship between this fungus and
armadillos even in non-endemic areas.
Frequent isolation of P. brasiliensis is usually observed in
mesenteric lymph nodes and the fungus has also been molecularly detected
in feces samples, suggesting that the armadillo infection might be
occurring by alternative routes, like the gastrointestinal tract
(Bagagli et al., 2008). Lungs, liver and spleen were the organs whereP. brasiliensis was detected in this study. As described by
Bagagli et al. (2008), after the fungus is inhaled by the respiratory
tract, the mycelial form can be transformed in yeast in the lungs and be
systemically disseminated in armadillos, in a very similar way to that
described in humans.
This fungus can survive long periods in the soil, and can also be found
inside armadillo burrows (Silva-Vergara et al., 2000; Bagagli and
Simões, 2005). The constant digging activity inside burrows may further
increase the exposure of armadillos to pathogen inhalation and, based on
Silva-Vergara et al. (2000), armadillo infection may increase the
long-term viability of the fungus.
Armadillo’s ecological studies may also favor the obtaining of relevant
information concerning the health status of a given environment.
Long-term surveillance health programs involving armadillos should be
encouraged, and the data obtained from these should help to better: 1)
Understand the prevalence data or occurrence of diverse parasites,
especially the zoonotic ones, in the ecosystems they occur; 2) Identify
the role of armadillos as reservoir hosts of different parasite species;
3) Provide precise geographic locations and disease risk map analysis;
4) Develop actions and preventive disease control initiatives
considering the parasites that can be transmitted by armadillos; and 5)
Develop low-cost strategies for health studies considering wild animals,
humans and their ecosystems.