Gastritis Caused by Multiple Nematospiroides dubius Infections

Abstract

Webster mice 6 to 8 weeks old were given 4 infections of 50 Nematospiroides dubius larvae each at 15-day intervals. Thirty minutes after the last inoculation some larvae had penetrated into the gastric mucosa, and eosinophils were observed in the submucosa in the cardiac region. By the 2nd hr large numbers of eosinophils, neutrophils, and mast cells were observed in the lamina propria and submucosa. Degenerative changes of the adjacent glandular epithelia of the stomach were also noted at this time. By 4 hr cellular infiltration, edema, and thrombosis was evident in the submucosa. Extensive edema, thrombosis, necrosis of the vascular wall, and vasculitis were observable in the submucosa and serosa, with severe degenerative changes in the parasitized glandular epithelia. Lymphadenitis was visible in the gastric node by the 8th hr. The gastric lesions increased with intense severity and had reached their peak at 12 hr, when leukocytic infiltration was evident in the submucosa and muscularis mucosae of the stomach. Lymphoid hyperplasia was evident in the gastric node at 4 days after last infection, and eosinophils and mast cells were sprinkled in the submucosa at 8 to 10 days after challenge. The gastric lesions subsided by the 12th day. The intestinal pathology in Webster mice following a single oral infection with Nematospiroides dubius was first reported by Baker (1954). Liu (1965a, b, 1966) described the pathology of the intestine, mesenteric lymph nodes, liver, and spleen in a resistant strain of Webster mice and a susceptible strain of C3H mice following primary infection and reinfection with N. dubius. Liu (1965a) reported that following oral infection, the third-stage larvae of N. dubius wandered into the deepest portion of the gastric mucosa of the fundic region for approximately 36 hr and provoked mild gastritis in the susceptible mice. The purpose of this investigation was to study the development of gastric pathology following oral challenge with N. dubius in Webster mice which had been immunized by previously receiving three oral infections of N. dubius (see Van Zandt, 1961). MATERIALS AND METHODS The strain of nematode, preparation of cultures, and method of inoculation have been described by Van Zandt (1961). Thirty-four Webster mice 6 to 8 weeks old of both sexes (Group I) were given 3 oral inoculations of 50 N. dubius larvae each at 15-day intervals. Thirty-four mice of the same strain, age, and sex (Group II) were used as controls and received no stimulating infections. * This study was funded in part by NIH Grant AI 10490-02. Fifteen days following the third oral inoculation, both groups of mice were treated with pyrantel tartrate supplied through the courtesy of Charles Pfizer & Son, Rahway, N. J. (60 mg,/kg of body weight) 4 days apart (Cypess and Van Zandt, 1973). Four additional control groups were used: these included (1) viability controls (given a single inoculation and killed 15 days later for determination of adult counts), (2) immunity controls (given stimulating infections, treated with the 2 oral drug doses, challenged 4 days later with 50 larvae, and killed 15 days later for determination of adult counts), (3) drug action controls (given stimulating infections, treated with the 2 oral drug doses, and killed 4 days later to check on the efficacy of treatment), and (4) drug residue controls (treated with the drug and given the challenging infection 4 days later to determine whether or not the drug had a residual effect on this infection ). Four days after the last anthelminthic treatment appropriate groups were orally infected with 50 larvae. Two mice from Groups I and II were killed at 30 min, 2, 4, 8, and 12 hr, and 2, 4, 6, 10, and 12 days after the 4th oral infection for pathological examination. All tissue samples for histopathological study were fixed in 10% formalin, embedded in paraffin, sectioned, and stained with hematoxylin eosin.