Assessing pig farm biosecurity measures for the control of Salmonella on European farms.

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.

Prioritization of pig farm biosecurity for control of Salmonella and hepatitis E virus infections: results of a European expert opinion elicitation.

BACKGROUND: In the literature, there is absent or weak evidence on the effectiveness of biosecurity measures to the control of Salmonella spp. and hepatitis E virus (HEV) on pig farms. Therefore, the present study aimed to collect, weigh, and compare opinions from experts on the relevance of several biosecurity measures. An online questionnaire was submitted to selected experts, from multiple European countries, knowledgeable on either HEV or Salmonella spp., in either indoor or outdoor pig farming systems (settings). The experts ranked the relevance of eight biosecurity categories with regards to effectiveness in reducing the two pathogens separately, by assigning a score from a total of 80, and within each biosecurity category they scored the relevance of specific biosecurity measures (scale 1-5). Agreement among experts was analysed across pathogens and across settings. RESULTS: After filtering for completeness and expertise, 46 responses were analysed, with 52% of the experts identified as researchers/scientists, whereas the remaining 48% consisted of non-researchers, veterinary practitioners and advisors, governmental staff, and consultant/industrial experts. The experts self-declared their level of knowledge but neither Multidimensional Scaling nor k-means cluster analyses produced evidence of an association between expertise and the biosecurity answers, and so all experts' responses were analysed together without weighting or adaptation. Overall, the top-ranked biosecurity categories were pig mixing; cleaning and disinfection; feed, water and bedding; and purchase of pigs or semen, while the lowest ranked categories were transport, equipment, animals (other than pigs and including wildlife) and humans. Cleaning and disinfection was ranked highest for both pathogens in the indoor setting, whereas pig mixing was highest for outdoor settings. Several (94/222, 42.3%) measures across all four settings were considered highly relevant. Measures with high disagreement between the respondents were uncommon (21/222, 9.6%), but more frequent for HEV compared to Salmonella spp. CONCLUSIONS: The implementation of measures from multiple biosecurity categories was considered important to control Salmonella spp. and HEV on farms, and pig mixing activities, as well as cleaning and disinfection practices, were perceived as consistently more important than others. Similarities and differences in the prioritised biosecurity measures were identified between indoor and outdoor systems and pathogens. The study identified the need for further research especially for control of HEV and for biosecurity in outdoor farming.

What is a biosecurity measure? A definition proposal for animal production and linked processing operations.

While biosecurity, a central component of the One Health concept, is clearly defined, a harmonized definition of the term ´biosecurity measure´ (BSM) is missing. In turn, particularly at the farm and policy level, this leads to misunderstandings, low acceptance, poor implementation, and thus suboptimal biosecurity along the food animal production chain. Moreover, different views on BSMs affects making comparisons both at the policy level as well as in the scientific community. Therefore, as part of the One Health EJP BIOPIGEE project, a work group i) collected and discussed relevant inclusion and exclusion criteria for measures to be considered in the context of biosecurity and ii) conducted a systematic literature review for potentially existing definitions for the term BSM. This exercise confirmed the lack of a definition of BSM, underlining the importance of the topic. In the pool of articles considered relevant to defining the term BSM, specific research themes were identified. Based on these outcomes, we propose a definition of the term BSM: "A biosecurity measure (BSM) - is the implementation of a segregation, hygiene, or management procedure (excluding medically effective feed additives and preventive/curative treatment of animals) that specifically aims at reducing the probability of the introduction, establishment, survival, or spread of any potential pathogen to, within, or from a farm, operation or geographical area." The definition provides a basis for policymakers to identify factual BSMs, highlights the point of implementation and supports to achieve the necessary quality standards of biosecurity in food animal production. It also enables clear, harmonized, cross-sectoral communication of best biosecurity practices to and from relevant stakeholders and thus contribute to improving biosecurity and thereby strengthen the One Health approach.