Effect of T. spiralis infection on intestinal motor activity in the fasted state.

We sought to determine the effects of Trichinella spiralis infection on small intestinal motor activity in the fasted state in dogs and relate it to clinical symptoms during the intestinal phase of trichinosis. Motor activity was recorded by strain gauge force transducers. Infection with T. spiralis resulted in a significant increase in the incidence and proximal origination of giant migrating contractions (GMCs) during the first 5 days postinfection. This was also the time when the dogs had diarrhea. The dogs were often restless and showed signs of discomfort during proximally originating GMCs. The incidence of retrograde giant contractions (RGCs) increased significantly on the 2nd and 3rd day postinfection. RGCs were followed by vomiting 71% of the time during infection. The migrating motor complex cycle length increased significantly, and this was due to intestinal "amyogenesia" and "dysmyogenesia". During these phenomena, electrical control activity was almost completely obliterated in the proximal half of the small intestine (amyogenesia) and became irregular and unstable in the distal half (dysmyogenesia). Intestinal amyogenesia and dysmyogenesia lasted up to 4 h and were terminated by a GMC. We conclude that diarrhea induced by T. spiralis infection is closely associated with an increase in the incidence and proximal origin of GMCs. These GMCs may also be the motor correlates of abdominal cramping and pain during the intestinal phase of trichinosis.