A free classified advertising website is a high-risk unregulated source of domestic wild boar, pot-bellied pigs, and their hybrids with domestic swine in Canada: Implications for African Swine Fever Risk Preparedness

Abstract

Invasive wild pigs are a global problem and are established in large areas across Canada. Domestic European wild boar were first introduced to Canadian farms in the 1980s, and their escape and intentional release have since led to free-ranging populations, which have expanded rapidly in numbers and range. Wild pigs are associated with widespread damage to crops and natural environments, as well as risks of disease transmission. African Swine Fever (ASF) is a highly contagious viral disease of global concern, that can spread between domestic and free-ranging swine and cause catastrophic economic impacts. As ASF preparedness requires a detailed understanding of the distribution and movements of all pig types, this paper aimed to characterize an unregulated grey swine market in Canada to understand risks to domestic swine production and potential contributions to free-ranging wild pig populations. Kijiji.ca is a free Canadian internet classified advertising service, almost exclusively cash-based with no receipts and few, if any, records kept of transactions. We monitored Kijiji for sales of domestic wild boar, pot-bellied pigs, and their hybrids across Canada over two months from April 28 - June 30, 2021. Data was collected from all advertisements, including how the seller labelled pigs breed, age, sex, number for sale, sexual intactness, presence of tattoos and/or ear tags, as well as the date and location of the posting. Locations were mapped and compared to the spatial distribution of existing free-ranging wild pigs in Canada to identify areas they were likely to facilitate new populations or potentially supplement and genetically diversify existing populations. We identified 151 advertisements on Kijiji, the most coming from Ontario (34.4%; n = 52) and Alberta (29.1%; n = 44), followed by Saskatchewan (11.3%; n = 17), British Columbia (10.6%; n = 16), Nova Scotia (7.3%; n = 11), New Brunswick (4.0%; n = 6), Manitoba (2.0%; n = 3), Quebec (0.7%; n = 1), and Prince Edward Island (0.7%; n = 1). No listings were observed in Newfoundland and Labrador, or Yukon, Nunavut and Northwest Territories. Overall, 62 (41%) of advertisements were within watersheds with existing wild pigs that may contribute to supplementing additional swine, and 89 (59%) were within watersheds where wild pigs have not yet been identified. African swine fever preparedness should include policies and action to address this unmonitored and unregulated sale of swine in Canada, including ear tags, tattoos, genetic analysis, and mandatory reporting.