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United States Department of Agriculture

Agricultural Research Service

Title: Persistence of Salmonella Enteritidis from One Day of Age until Maturity in Experimentally Infected Egg-Type Chickens

Authors
item Gast, Richard
item Holt, Peter

Submitted to: Journal Of Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 3, 1998
Publication Date: N/A

Interpretive Summary: The effectiveness of efforts to reduce egg-transmitted Salmonella enteritidis (SE) infections in humans is largely dependent on controlling the incidence of this pathogen in commercial laying flocks. Identifying the sources of introduction of SE into laying flocks is essential for developing effective control strategies. The present study investigated the epotential for SE infections acquired by newly hatched chicks to persist until the age at which hens began to lay eggs. After chicks were given an oral dose of SE at 1 day of age, many birds continued to harbor this organism in their intestinal tracts and shed it in their feces through at least 6 months of age. One hen produced at least 2 eggs with SE in the liquid contents. Chickens exposed to SE shortly after hatching can apparently remain infected until maturity, at which time they might produce contaminated eggs or spread the infection to other susceptible, previously unexposed hens. This suggests that efforts to detect and control SE infection in young poultry can indeed have direct relevance to the overall goal of reducing egg contamination.

Technical Abstract: In each of 2 replicate trials, 1-day-old chicks were inoculated orally with a phage type 13 Salmonella enteritidis isolate (resistant to nalidixic acid). Although S. enteritidis was found in the livers, spleens, and ceca of all sampled chicks at 1 week post-innoculation, colonization generally persisted beyond 4 weeks post-inoculation only in the ceca. Nearly half of the remaining hens were still shedding S. enteritidis in their feces at 24 weeks of age, but only 1 of 62 hens laid eggs that were internally contaminated with S. enteritidis during the initial 4-6 weeks of egg production. Chickens exposed to S. enteritidis shortly after hatching can apparently remain infected until maturity, at which time they might produce contaminated eggs or spread the infection to other susceptible, previously unexposed hens. This suggests that efforts to detect and control SE infection in young poultry can indeed have direct relevance to the overall goal of reducing egg contamination.

Last Modified: 4/25/2014
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