The results of the current experiment indicate the apparent absence of systemic stimuli in the disease mechanisms of T. colubriformis infection.
While infection of Thiry-Vella loops in 2 sheep was associated with severe atrophy and a marked increase in secretory activity of such loops, the remaining intestine in continuity with the alimentary tract (functional intestine) appeared normal. Similarly, per os infection, which produced varying degrees of disorders of functional intestine, was not accompanied by any changes in the secretory function or mucosal morphology (other than those resulting from the isolation procedure) of Thiry-Vella loops. In one severely affected sheep (per os infection), the secretory function of the Thiry-Vella loop was diminished. However, it would appear that the reduction was associated with a water stress rather than being a direct effect of parasitism.
The absence of anorexia in loop infected sheep despite the severe lesion might indicate the unimportance of gut pain as a mediator of anorexia in parasitisms. However, this aspect requires further work since the by-pass procedure and the environment in by-passed intestine may diminish the manifestation of gut pain.