Immunity in Volunteers Recovered From Non-Bacterial Gastroenteritis 1

The afebrile type (1) of acute infectious non- bacterial gastroenteritis seems to be an extremely common diarrhea in the Northeastern United States. It occurs yearly in some families and com- munities (2, 3). Whether the recurrences are due to the early waning of immunity or to the ex- istence of immunologically distinct agents has not been determined. Following an attack of gastro- enteritis evoked by the Marcy strain (4), which is presumably a virus, an effective immunity de- velops in volunteers (1, 4-6), and in an earlier report the opinion was expressed that immunity probably does not persist for long (5). The present study shows that individuals who recov- ered from experimental Marcy gastroenteritis more than a year before were fully resistant to re- infection. It may well be, therefore, that the sec- ond explanation of the recurrences is the correct one and more than one antigenically distinct agent exists.