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