Salmonella spp. is a common zoonotic pathogen, causing gastrointestinal infections in people. Pigs and pig meat are a major source of infection. Although farm biosecurity is believed to be important for controlling Salmonella transmission, robust evidence is lacking on which measures are most effective. This study enrolled 250 pig farms across nine European countries. From each farm, 20 pooled faecal samples (or similar information) were collected and analysed for Salmonella presence. Based on the proportion of positive results, farms were categorised as at higher or lower Salmonella risk, and associations with variables from a comprehensive questionnaire investigated. Multivariable analysis indicated that farms were less likely to be in the higher-risk category if they had '<400 sows'; used rodent baits close to pig enclosures; isolated stay-behind (sick) pigs; did not answer that the hygiene lock/ anteroom was easy to clean; did not have a full perimeter fence; did apply downtime of at least 3 days between farrowing batches; and had fully slatted flooring in all fattener buildings. A principal components analysis assessed the sources of variation between farms, and correlation between variables. The study results suggest simple control measures that could be prioritised on European pig farms to control Salmonella.

Department of Biological Safety German Federal Institute for Risk Assessment Berlin Germany

Department of Epidemiological Sciences Animal and Plant Health Agency Weybridge Addlestone UK

Department of Preclinical Sciences and Infectious Diseases Faculty of Veterinary Medicine and Animal Sciences University of Life Sciences Poznan Poland

Department of Public Health Masaryk University Brno Czech Republic

Department Population Health Sciences Faculty of Veterinary Medicine Utrecht University Utrecht The Netherlands

Division for Animal Health Austrian Agency for Health and Food Safety Mödling Austria

Emerging Zoonoses Unit Istituto Superiore di Sanità Rome Italy

Institute of Veterinary Medicine and Animal Sciences Estonian University of Life Sciences Tartu Estonia

Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise Giuseppe Caporale Teramo Italy

Istituto Zooprofilattico Sperimentale della Lombardia e Dell'Emilia Romagna Brescia Italy

Ministry of Agriculture Environment and Climate Protection Potsdam Germany

National Centre for Laboratory Research and Risk Assessment Tartu Estonia

National Diagnostic and Research Veterinary Medicine Institute Sofia Bulgaria

National Veterinary Research Institute Puławy Poland

University of Veterinary Medicine Vienna Vienna Austria

Veterinary Research Institute Brno Czech Republic

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