Pathology of Nematospiroides dubius. I. Primary infections in C 3H and Webster mice

Abstract

Webster and C 3H mice were given 200 Nematospiroides dubius larvae each. As early as 4 hours after oral inoculation, larvae were found in the gastrointestinal mucosa. They moved into the deepest portion of the gastric mucosa of the fundic region and provoked local gastritis in C 3H mice. The larvae left the gastric mucosa within 36 hours after infection. By this time, in the mucosa of the small intestine, the adjacent tissue, including capillaries around the invading larvae, was necrotized; and newly formed thrombi were present in the lumen of the damaged vessels. The larvae encysted in the muscularis externa on the third day. Penetration of the larvae and their necrotizing substances caused local tissue destruction and inflammation in the mucosa and submucosa of the small intestine. The lesions thus produced were milder than those provoked by the subsequent emergence (by the eighth day) of the juvenile worms and by the substances they released. After emergence of the larvae, the lesions were repaired completely within 21 days after infection. Lymphadenitis and hyperplasia of reticuloendothelial tissue in the mesenteric lymph glands, nonspecific hepatitis, and splenomegaly were assumed to be due to mechanically produced tissue damage in the intestines resulting from larval invasion, and to the allergenic factor of the substances released by the parasites.