The histopathology of experimental strongyloidiasis.

An investigation of the pathologic events occurring during experimental Strongyloides ratti infection in rats was done. The chronologic sequence of the cellular responses to the infecting larvae as they migrated through the skin and lungs was determined. Larvae penetrate the skin very quickly, eliciting considerable mast cell degranulation within the first few minutes, a modest neutrophil response within the first few hours, and an occasional mononuclear response within the first 2 days. The larval passage in the lungs appears to cause little damage except for microhemorrhages and an occasional microabscess. In the intestine S ratti adult worms lie in the cryptae without penetrating mucosa, and except for an increase in the number of mast cells at the time of expulsion (Days 20--25), there is no detectable cellular response. Differences from the human disease are discussed.