| Abstract: | Chagasic megaoesophagus and megacolon are characterised by motor abnormalities
related to enteric nervous system lesions and their development seems to be related
to geographic distribution of distinct Trypanosoma cruzi
subpopulations. Beagle dogs were infected with Y or Berenice-78 (Be-78) T.
cruzi strains and necropsied during the acute or chronic phase of
experimental disease for post mortem histopathological evaluation of
the oesophagus and colon. Both strains infected the oesophagus and colon and caused
an inflammatory response during the acute phase. In the chronic phase, inflammatory
process was observed exclusively in the Be-78 infected animals, possibly due to a
parasitism persistent only in this group. Myenteric denervation occurred during the
acute phase of infection for both strains, but persisted chronically only in Be-78
infected animals. Glial cell involvement occurred earlier in animals infected with
the Y strain, while animals infected with the Be-78 strain showed reduced glial
fibrillary acidic protein immunoreactive area of enteric glial cells in the chronic
phase. These results suggest that although both strains cause lesions in the
digestive tract, the Y strain is associated with early control of the lesion, while
the Be-78 strain results in progressive gut lesions in this model. |
