Intestinal distribution of Trichinella spiralis in rats.

Intestinal distribution of Trichinella spiralis was studied in mature and suckling Sprague-Dawley rats. Position of Trichinella along the small intestine was defined by a median value for the population. A range, 90% of total population, gave a relatively precise determination of microhabitat width. The normal position of Trichinella following an oral infection is in the duodenum, but position of Trichinella in mature rats is more anterior than position of Trichinella in suckling rats. Intestinal inoculation of Trichinella larvae into the jejunum and ileum revealed that worms remained at the site of inoculation and did not migrate to the duodenum. Trichinella is able to utilize the entire small intestine but its normal position is the duodenum. The position of Trichinella in the anterior region of the small intestine probably is related to physiological factors of the intestine and thereby host dominated.