Occupational Health & Safety

Salmonellosis

Enteric infection with Salmonella spp (PDF). has a worldwide distribution among humans and animals (PDF). Ornamental fish tanks (PDF) have been demonstrated to serve as a reservoir for multi drug-resistant Salmonella enterica serovar Paratyphi B. Among the laboratory animal species, rodents from many sources are now free from salmonella infection, due to successful programs of cesarean rederivation, accompanied by rigorous management practices to exclude the recontamination of animal colonies. The pasteurization of feeds has also contributed to the control of salmonellosis in the laboratory.

However, despite the efforts to eliminate the organism in laboratory animal populations, carriers continue to occur, as a result of infection by contaminated food, or other environmental sources of contamination. These carriers represent a source of infection for other animals and for personnel who work with animals.

Results of recent surveys in dogs and cats have indicated that the prevalence of infection remains approximately 10% among random-source animals. Salmonella continue to be recorded frequently among recently imported nonhuman primates. Infection with Salmonella is nearly ubiquitous among reptiles. Avian sources are often implicated in foodborne cases of human salmonellosis. Birds in a laboratory animal facility should be considered likely sources for zoonotic infection.

The organism is transmitted by the fecal-oral route, via food derived from infected animals, or from food contaminated during preparation, contaminated water, or direct contact with infected animals.

Salmonella infection produces an acute, febrile enterocolitis. Septicemia and focal infections occur as secondary complications. Focal infections can be localized in any tissue of the body, so the disease has diverse manifestations.

Whenever possible, animals known to be Salmonella free should be used in laboratory animal facilities. The use of antibiotic treatment of Salmonella-infected animals as a means of controlling the organism in a laboratory animal facility may be unrewarding, because antibiotic treatment can prolong the period of communicability.

Personnel should rely on the use of protective clothing, personal hygiene, and sanitation measures to prevent the transmission of the disease. Animal Biosafety Level 2 (PDF) is recommended for activities using naturally or experimentally infected animals.