Stomach, Forestomach - Parasite, Metazoan

Stomach, Forestomach - Parasite, Metazoan in a male F344/N rat from a chronic study. Nematodes (arrows) are present within the mucosa of the forestomach.
Figure 1 of 2
comment:
Because of current husbandry practices, nematode infections are rare. However, Gongylonema spp. have been seen in the forestomach of rats. Gongylonema nematodes are metazoan parasites most frequently found in the epithelium of the upper gastrointestinal tract, including the esophagus, tongue, buccal cavity, and forestomach ( Figure 1

recommendation:
Nematodes are to be diagnosed as "parasite, metazoan" but not graded. If the genus species can be identified it should be noted in the pathology narrative. Accompanying inflammation or other associated lesions should not be diagnosed separately unless the pathologist feels it is due to a different pathologic process or it is severe enough to warrant a separate diagnosis.references:
Stookey JL, Moe JB. 1978. The respiratory system. In: Pathology of Laboratory Animals, vol 1 (Benirschke K, Garner FM, Jones TC, eds). Springer, New York, 71-113.
Web page last updated on: November 24, 2014