Didelphis marsupialis, the most important sylvatic
reservoir of Trypanosoma cruzi, can also maintain in
their anal scent glands the multiplicative forms only
described in the intestinal tract of triatomine bugs. A study
of 21 experimentally and 10 naturally infected opossums with
T. cruzi was undertaken in order to establish the
histopathological pattern under different conditions.
Our results showed that the inflammation was predominantly
lymphomacrophagic and more severe in the naturally infected
animals but never as intense as those described in Chagas'
disease or in other animal models.
The parasitism in both groups was always mild with very scarce
amastigote nests in the tissues. In the experimentally
infected animals, the inflammation was directly related to
the presence of amastigotes nests.
Four 24 days-old animals, still in embryonic stage, showed
multiple amastigotes nests and moderate inflammatory
reactions, but even so they survived longer and presented
less severe lesions than experimentally infected adult mice.
Parasites were found in smooth, cardiac and/or predominantly
striated muscles, as well as in nerve cells. Differing from
the experimentally infected opossums parasitism in the
naturally infected animals predominated in the heart,
esophagus and stomach. Parasitism of the scent glands did not
affect the histopathological pattern observed in