Infectious agents in feral swine in Ohio, USA (2009-2015): A low but evolving risk to agriculture and public health

As highly mobile and prolific animals, feral swine threaten public and livestock health. To quantify these threats, we analyzed disease surveillance samples to estimate the prevalence of key pathogens and parasites in feral swine captured in Ohio. Between 2009 and 2015, samples from 205 feral swine were tested for up to 13 pathogens. Methicillin susceptible Staphylococcus aureus was cultured from 29 of 138 (21%) individuals and antibodies to Leptospira spp. (16/69; 23%), Toxoplasma gondii (11/76; 15%), Trichinella spiralis (4/69; 6%), hepatitis E virus (1/32; 3%), Brucella spp. (2/138; 1%), and influenza A virus (2/176; 1%) were also detected. Lungworms (Metastrongylus spp.) were frequently identified (46/55; 84%). Evidence of infection or exposure was not detected to Mycobacterium bovis, classical swine fever, pseudorabies, and porcine reproductive and respiratory syndrome. All positive Brucella and hepatitis E virus samples and 63% (10/16) of the positive Leptospira spp. samples came from individuals identified as illegal out-of-state feral swine introductions. Results indicated an overall low prevalence of pathogens in feral swine in Ohio; however, the importation of live feral swine from other states remained an important concern for pathogen introduction and spread.