David S. Schreiber

Clinical Immunity in Acute Gastroenteritis Caused by Norwalk Agent

To examine immunity in viral gastroenteritis, we challenged and then rechallenged 12 volunteers with Norwalk agent and evaluated symptoms, jejunal biopsies and serum antibody. With the first challenge, gastroenteritis developed in six volunteers but not in the others. When rechallenged 27 to 42 months later, the six who became ill initially again had gastroenteritis with jejunal lesions; in the six previously immune volunteers illness or jejunal lesions did not develop. Four of five ill volunteers had increases in serum antibody to Norwalk agent after both challenges. Serum antibody did not increase in three immune volunteers after either challenge. Four volunteers who had twice become ill underwent a third challenge four to eight weeks after their second illness. In one gastroenteritis developed; in three, it did not. These findings indicate two forms of immunity for viral gastroenteritis, one of short and the other of long duration. Factors other than serum antibody appear important in immunity to Norwalk gastroenteritis.

The mucosal lesion of the proximal small intestine in acute infectious nonbacterial gastroenteritis.

Abstract The pathogenesis of acute infectious nonbacterial gastroenteritis, a common illness, is uncertain. Indeed, the morphology of the mucosa of the small intestine in this disease has not been described. Fifteen volunteers with normal base-line intestinal biopsies ingested orally stool filtrate containing Norwalk agent. Twelve acquired clinical gastroenteritis and abnormal intestinal histology with mucosal inflammation, absorptive cell abnormalities, villous shortening, crypt hypertrophy and increased epithelial-cell mitoses. Abnormal mucosal histologic findings persisted for at least four days after clinical symptoms cleared. Biopsies six to eight weeks after illness were normal. In one of three asymptomatic volunteers a typical mucosal lesion developed; biopsies in the other two remained normal. These findings indicate that a characteristic intestinal lesion accompanies acute infectious nonbacterial gastroenteritis, is demonstrable a few hours before clinical illness, can occur in asymptomatic infec...

Abnormal gastric motor function in viral gastroenteritis

Nausea and vomiting occur commonly with gastroenteritis caused by parvovirus-like agents. Infection results in histologic injury to the small bowel mucosa, but the gastric mucosa remains unaffected. We have studied gastric emptying of liquids serially in 10 volunteers before and after ingestion of the parvovirus-like agents, Norwalk and Hawaii viruses. The five subjects who developed illness all showed marked delays in gastric emptying, while the five well subjects had no alteration of emptying. Five addition volunteers who developed Norwalk virus gastroenteritis underwent serial studies of gastric secretion of hydrochloric acid, pepsin, and intrinsic factor. No change was detected in either basal or betazole-stimulated secretion of these three substances during the course of illness. The nausea and vomiting accompanying this type of viral gastroenteritis may result from abnormal gastric motor function.

Structure of the Gastric Mucosa in Acute Infectious Nonbacterial Gastroenteritis

It is now well documented that a characteristic mucosal lesion of the proximal small intestine is present in acute nonbacterial gastroenteritis. To determine whether a gastric mucosal lesion also accompanies this illness, stool filtrate containing Norwalk agent was given orally to 15 volunteers after base line biopsies of gastric fundal and/or antral mucosa had been obtained. Gastric fundal and/or antral biopsies were then obtained serially between 24 and 168 hr after administration of the inoculum. Nine volunteers developed symptoms of gastroenteritis. gastric biopsies from those with normal base line fundal and/or antral biopsies remained normal during and after clinical illness. Those volunteers who had mild to moderate gastritis in their base line biopsies showed persistence but no progression of the lesion during illness. In 4 of the volunteers who became ill, intestinal biopsies were available and showed the typical gastroenteritis lesion. These results indicate that acute infectious nonbacterial gastroenteritis induced by Norwalk agent is not associated with histologically detectable gastric mucosal lesion.