title: Evaluation of the respiratory route as a viable portal of entry for Salmonella in poultry via intratracheal challenge of Salmonella Enteritidis and Salmonella Typhimurium.
abstract: Experimental and epidemiological evidence suggests that primary infection of Salmonella is by the oral-fecal route for poultry. However, the airborne transmission of Salmonella and similar enteric zoonotic pathogens has been historically neglected. Increasing evidence of Salmonella bioaerosol generation in production facilities and studies suggesting the vulnerabilities of the avian respiratory architecture together have indicated the possibility of the respiratory system being a potential portal of entry for Salmonella in poultry. Presently, we evaluated this hypothesis through intratracheal (IT) administration of Salmonella Enteritidis and Salmonella Typhimurium, as separate challenges, in a total of 4 independent trials, followed by enumeration of cfu recovery in ceca-cecal tonsils and recovery incidence in liver and spleen. In all trials, both Salmonella Enteritidis and Salmonella Typhimurium, challenged IT colonized cecae to a similar or greater extent than oral administration at identical challenge levels. In most trials, chickens cultured for cfu enumeration from IT-challenged chicks at same dose as orally challenged, resulted in an increase of 1.5 log higher Salmonella Enteritidis from ceca-cecal tonsils and a much lower dose IT of Salmonella Enteritidis could colonize ceca to the same extent than a higher oral challenge. This trend of increased cecal colonization due to IT challenge was observed with all trails involving week-old birds (experiment 2 and 3), which are widely considered to be more difficult to infect via the oral route. Liver-spleen incidence data showed 33% of liver and spleen samples to be positive for Salmonella Enteritidis administered IT (10(6) cfu/chick), compared with 0% when administered orally (experiment 2, trial 1). Collectively, these data suggest that the respiratory tract may be a largely overlooked portal of entry for Salmonella infections in chickens.
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville 72701.
authors.forename: G
authors.initials: G
authors.lastname: Kallapura
authors.forename: M J
authors.initials: MJ
authors.lastname: Morgan
authors.forename: N R
authors.initials: NR
authors.lastname: Pumford
authors.forename: L R
authors.initials: LR
authors.lastname: Bielke
authors.forename: A D
authors.initials: AD
authors.lastname: Wolfenden
authors.forename: O B
authors.initials: OB
authors.lastname: Faulkner
authors.forename: J D
authors.initials: JD
authors.lastname: Latorre
authors.forename: A
authors.initials: A
authors.lastname: Menconi
authors.forename: X
authors.initials: X
authors.lastname: Hernandez-Velasco
authors.forename: V A
authors.initials: VA
authors.lastname: Kuttappan
authors.forename: B M
authors.initials: BM
authors.lastname: Hargis
authors.forename: G
authors.initials: G
authors.lastname: Tellez
mesh_terms: D000280:Administration, Inhalation; D000284:Administration, Oral; D000336:Aerosols / Q000008:administration & dosage; D000818:Animals; D002432:Cecum / Q000382:microbiology; D002645:Chickens; D005243:Feces / Q000382:microbiology; D008099:Liver / Q000382:microbiology; D011201:Poultry Diseases / Q000382:microbiology / Q000635:transmission*; D012481:Salmonella Infections, Animal / Q000382:microbiology / Q000635:transmission*; D012477:Salmonella enteritidis / Q000502:physiology*; D012486:Salmonella typhimurium / Q000502:physiology*; D013154:Spleen / Q000382:microbiology
chemical_list: D000336:Aerosols
keywords: Salmonella Enteritidis; Salmonella Typhimurium; broiler; intratracheal challenge