title: Pathogenicity and persistence of Salmonella enteritidis and egg contamination in normal and infectious bursal disease virus-infected leghorn chicks.
abstract: The pathogenicity and persistence of Salmonella enteritidis (SE) phage type 8 and resulting egg contamination in normal and infectious bursal disease virus (IBDV)-infected white leghorn chicks were evaluated over 34 weeks and in some birds over a 64-week period. Four hundred 1-day-old specific-pathogen-free (SPF) straight-run white-leghorn chickens were allotted into four treatment groups: negative control, IBDV-infected, IBDV+SE-infected, and SE-infected. Chicks were infected with IBDV at 1 day of age and with SE phage type 8 at 2 days of age. SE persisted in the gut of more than 50% of the chicks of both SE-infected groups through 34 weeks postinoculation (PI), and SE could still be isolated from cloacal/rectal swabs taken at 64 weeks. IBDV+ SE-infected chicks had severe gross lesions and significantly (P < 0.001) higher mortality (32%) than the negative control (1%), IBDV-infected (10%), and SE-infected (1%) groups. Gross lesions consisting of fibrinous pericarditis, perihepatitis, peritonitis, airsacculitis, and inspissated yolk were observed only in the IBDV+SE-infected group. SE isolations from internal organs of chickens in the IBDV+SE-infected group decreased from 83% at 8 weeks to 0% at 14 weeks PI; isolations from the SE-infected group decreased from 50% at 8 weeks to 0% at 10 weeks PI. Salmonella isolations increased from 0% to 14% in both groups at 18 weeks, corresponding with the time of sexual maturity. Of the 1,050 eggs cultured from the IBDV+SE-infected group, SE was isolated from 88 shells, five albumens, and two yolks. In contrast, of 1,258 eggs from the SE-infected group, 33 shells and none of the albumens and yolks were positive for SE. All eggs that had SE-positive contents also had SE-positive shells.
authors.affiliation: Department of Animal, Veterinary and Aquatic Sciences, University of Maine, Orono 04469-5735, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Phillips
authors.forename: H M
authors.initials: HM
authors.lastname: Opitz
mesh_terms: D000818:Animals; D018175:Birnaviridae Infections / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D002645:Chickens; D004531:Eggs / Q000382:microbiology*; D005260:Female; D007243:Infectious bursal disease virus; D009928:Organ Specificity; D011201:Poultry Diseases; D012481:Salmonella Infections, Animal / Q000150:complications / Q000473:pathology*; D012477:Salmonella enteritidis / Q000302:isolation & purification* / Q000472:pathogenicity*; D013997:Time Factors; D014774:Virulence