title: Observations related to the Salmonella EU layer baseline survey in the United Kingdom: follow-up of positive flocks and sensitivity issues.
abstract: A follow-on study was carried out on 23 holdings identified as Salmonella positive in the 2004/2005 European Union (EU) baseline survey of Salmonella in laying hens. Eleven of 13 cage and 4/7 floor houses remained positive for Salmonella when the new flock was tested, and from 10/13 cage and 3/7 floor houses a Salmonella of the same serovar/phage type as found in the EU survey was isolated. There was a high correlation between the level of contamination in the houses at the time of the EU survey and in the follow-on flock. On seven occasions the house identified as positive in the EU survey was sampled after cleaning and disinfection but before a new flock was placed, and in all of them Salmonella could be isolated from the houses. The observed number of infected houses in infected holdings suggests that the holding-level prevalence in the United Kingdom would be about 21% higher than the results obtained in the EU survey.
authors.affiliation: Department of Food and Environmental Safety, Veterinary Laboratories Agency, Addlestone, Surrey, UK. j.carrique-mas@vla.defra.gsi.gov.uk
authors.forename: J J
authors.initials: JJ
authors.lastname: Carrique-Mas
authors.forename: M
authors.initials: M
authors.lastname: Breslin
authors.forename: L
authors.initials: L
authors.lastname: Snow
authors.forename: M E
authors.initials: ME
authors.lastname: Arnold
authors.forename: A
authors.initials: A
authors.lastname: Wales
authors.forename: I
authors.initials: I
authors.lastname: McLaren
authors.forename: R H
authors.initials: RH
authors.lastname: Davies
mesh_terms: D000818:Animals; D001434:Bacteriophage Typing; D003625:Data Collection; D004783:Environmental Microbiology; D005243:Feces / Q000382:microbiology; D005500:Follow-Up Studies; D011200:Poultry; D011201:Poultry Diseases / Q000453:epidemiology*; D012475:Salmonella / Q000145:classification* / Q000302:isolation & purification*; D012481:Salmonella Infections, Animal / Q000453:epidemiology*; D012680:Sensitivity and Specificity; D012703:Serotyping; D013223:Statistics as Topic; D006113:United Kingdom / Q000453:epidemiology