A literature review to gather the scientific evidence for an African Swine Fever virus (ASFV) exposure assessment of US domestic pigs raised in total confinement and/or with outdoor access to ASFV-infected feral swine

Abstract

Feral swine are an invasive species in the United States (US) that cause damage to agriculture property, livestock, natural resources (water and land), cultural sites, and historic places. Feral swine can also physically injure pets and people. Feral swine have been reported in at least 35 US states and have an estimated population of >6 million. There are also feral swine in Canada, especially in the plains Prairie Provinces (i.e., Alberta, Saskatchewan, and Manitoba). In addition to the environmental damage and physical harm, feral swine can and may harbor numerous pathogens, both swine-specific and zoonotic. African Swine Fever virus (ASFV), the causative agent of African Swine Fever (ASF), is arguably the pathogen of major concern. ASF is a foreign animal disease of high consequence, and although never diagnosed in the US, its introduction and subsequent spread would have myriad negative consequences for US domestic pig populations and the pork industry. In the US, the feral swine range map overlaps that of domestic pigs. This literature review describes the potential pathways of ASFV transmission between feral swine and domestic pigs, with a focus on direct transmission pathways. Since it is imperative that preventative measures are in place to prevent contact between feral swine and domestic pigs, the various mitigations implemented in ASF-infected countries, historically and currently, that were identified in the search of the published literature and case reports to decrease and/or eliminate ASFV transmission pathways for feral swine and domestic pigs are also reviewed and summarized.