Table 1.

Potential risk factors analysed from questionnaire.

Housing	Management	Biosecurity/hygiene
Type of pen (slatted, push-through, straw yard)	Number of staff Number of pigs on farm Time as a pig farm Age groups housed separately Feed source Sick pens Reintegration of recovered pigs Bedding source Bedding type Feeder/drinker systems	Staff contact with other pigs Visitors who have contact with other pigs Water supply (mains or borehole) Drainage Presence of wildlife species Proximity of waterways, scrubland, pig wastes, cattle wastes, or sewage treatment/landfill sites Feed storage (capacity and sealed/open bins) Presence of biosecurity measures (boot dips, wheel wash, and visitor/staff clothing) Pigs loaded at perimeter Site contained within perimeter fence Rodent controls Disinfectant: type and frequency