09 June 2010
In 2004/05, all European Union member states were required to carry out standardised prevalence surveys to establish the baseline prevalence of Salmonella in commercial laying flocks. As part of the survey in Great Britain, additional data were collected from 380 of the enrolled laying hen holdings to investigate risk factors for Salmonella at farm level. Using a multivariable logistic model weighted to account for the survey design, several factors significantly associated with Salmonella and Salmonella Enteritidis status were identified. Larger holdings (>or=30,000 birds) were found to be at higher risk of Salmonella, while vaccination, providing foot dips with brushes, washing and disinfecting the house at depopulation, having a clean car park away from house, using an independent or other non-company source of feed, being over 1 km from the nearest neighbouring farm and the presence of cats and dogs on the farm or on contiguous farms reduced the risk of any Salmonella serovars being present. Factors found to be associated specifically with an increased risk of S Enteritidis infection included holding size and frequent sightings of rats or mice. Non-caged systems, vaccination, the use of a non-company feed source, running the site as all-in/all-out and the presence of cats and dogs on the farm were associated with a reduced risk (Vet Rec 166:579-586, 2010).