Incidence of Members of the Salmonella Group in Rats

Abstract

The examination of fecal specimens by inoculation of 8 to 12 pellets into tetrathionate broth and streaking after 18-24 hrs. on bismuth-sulphite agar demonstrated the shedding of the infective organism by 15 of 24 rats fed 100 organisms by stomach tube. In some instances passage began on the 1st day and persisted in a few individuals as long as the 34th day. This intermittent excretion over a period of 7 weeks indicates the possible existence of the carrier state in a small number of animals so infected. Transmission of infection from infected rat to cage mates and subsequent infection by the latter of additional normal animals has been shown to date through 6 colonies. High agglutinin titers persisting for at least 4 months indicate that sero-logical studies may lead to false conclusions in tracing the source of Salmonella food poisoning. Examination of fecal specimens from 800 laboratory rats demonstrates that they are not normally carriers of Salmonella.