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Direct and indirect pathways for the spread of African swine fever and other porcine infectious diseases: An application of the mental models approac
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  • Francesco Galli,
  • Brian Friker,
  • Angela Bearth,
  • Salome Duerr
Francesco Galli
Universitat Bern Veterinary Public Health Institute

Corresponding Author:[email protected]

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Brian Friker
Universitat Bern Veterinary Public Health Institute
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Angela Bearth
Eidgenossische Technische Hochschule Zurich Institut fur Umweltentscheidungen
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Salome Duerr
Universitat Bern Veterinary Public Health Institute
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In this study, we investigated the occurrence of direct and indirect infectious disease transmission pathways among pig farms in Switzerland, as well as their specific relevance for the spread of African swine fever, porcine reproductive and respiratory syndrome (PRRS), and enzootic pneumonia. Data were collected using an adapted mental models approach, involving initial interviews with experts in the field of pig health and logistics, semi-structured interviews with pig farmers, and a final expert workshop, during which all identified pathways were graded by their predicted frequency of occurrence, their likelihood of spread of the three diseases of interest, and their overall relevance considering both parameters. As many as 24 disease pathways were identified in four areas: pig trade, farmer encounters, external collaborators, and environmental or other pathways. Two thirds of the pathways were expected to occur with moderate-to-high frequency. While both direct and indirect pig trade transmission routes were highly relevant for the spread of the three pathogens, pathways from the remaining areas were especially important for PRRS due to higher spread potential via aerosols and fomites. In addition, we identified factors modifying the relevance of disease pathways, such as farm production type and affiliation with trader companies. During the interviews, we found varying levels of risk perception among farmers concerning some of the pathways, which affected adherence to biosecurity measures and were often linked to the degree of trust that farmers had towards their colleagues and external collaborators. Our findings highlight the importance of integrating indirect disease pathways into existing surveillance and control strategies and in disease modelling efforts. We also propose that biosecurity training aimed at professionals and risk communication campaigns targeting farmers should be considered to mitigate the risk of disease spread through the identified pathways.
16 Jan 2022Submitted to Transboundary and Emerging Diseases
16 Jan 2022Submission Checks Completed
16 Jan 2022Assigned to Editor
20 Jan 2022Reviewer(s) Assigned
26 Feb 2022Review(s) Completed, Editorial Evaluation Pending
28 Feb 2022Editorial Decision: Revise Minor
30 Apr 20221st Revision Received
02 May 2022Submission Checks Completed
02 May 2022Assigned to Editor
05 May 2022Reviewer(s) Assigned
25 May 2022Review(s) Completed, Editorial Evaluation Pending
26 May 2022Editorial Decision: Accept
Sep 2022Published in Transboundary and Emerging Diseases volume 69 issue 5. 10.1111/tbed.14605