Rodents may serve as biologic vectors that can amplify salmonella
and disseminate these bacteria between poultry flocks (9). Wild rats,
in particular, have been reported to be naturally infected by
Salmonella Pullorum (21,22). In orally inoculated laboratory rats,
the organism has been reisolated from internal organs and the
intestinal tract and was found to persist for many days in submandibular
lymph nodes (19). Salmonella Pullorum was isolated from
the intestine of one rat on the index farm. Because rats had access to
contaminated chicken litter at the time of entrapment, this isolate
may have resulted from passive transport of contaminated ingesta
through the rat’s digestive tract or it may reflect true colonization of