Occurrence of wild boar and outdoor pigs, and location of selected pig farms. Map of Switzerland showing communes with wild boar occurrence (grey areas) and outdoor piggeries (dots). Black dots: farms selected to study risk factors for contacts between wild boar and outdoor pigs in 2009–2010; white dots: not selected farms.
Wu et al. BMC Veterinary Research 2012 8:116 doi:10.1186/1746-6148-8-116