Pathogen presence in feral pigs and their movement around two commercial piggeries in Queensland, Australia.

Feral pigs are wild animal reservoirs of infectious pathogens transmissible to other species, all of which are transmissible to domestic pigs. The objective of this study was to detect the presence of harmful production-limiting pathogens; Brucella suis, Leptospira species, Lawsonia intracellularis, Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae in a feral pig population within a 10 km radius of two large-scale commercial piggeries in Southern Queensland, Australia. The movement pattern of six pigs within the feral population was also investigated using geographic positioning system collars. All pathogens were present in the feral pig population except for A pleuropneumoniae. The true seroprevalence (TP) from 83 serum samples was 10.5 per cent for B suis, 48.6 per cent for Leptospira species, 100 per cent for L intracellularis and 42.1 per cent for M hyopneumoniae. Of 72 lung samples, 27.6 per cent were positive for M hyopneumoniae. Serum samples from 86 domestic sows within the study region were positive for Leptospira species (TP 2.1 per cent), L intracellularis (TP 100 per cent) and M hyopneumoniae (TP 100 per cent). The majority of feral pig movement was within 5 km of the piggeries, with one approaching to 100 m of the free-range piggery. The presence of pathogens in feral pigs in such close proximity to commercial piggeries could pose a biosecurity risk.

Vaccination of feral pigs (Sus scrofa) using iophenoxic acid as a simulated vaccine.

OBJECTIVES: To develop an encapsulation method for delivery of vaccines to feral pigs, and quantify the effect of iophenoxic acid on captive feral pig blood iodine concentrations to assist in investigation of factors affecting vaccine uptake. DESIGN AND METHODS: Feral pigs were administered iophenoxic acid by oral gavage, and consumption was assessed for different encapsulation methods in baits. Blood iodine concentrations were monitored for eight days after consumption. The relationship between dose rate, time since dosing and blood iodine concentration was assessed for gavaged and baited captive feral pigs. Wild feral pigs were baited with PIGOUT baits containing 20 mg of encapsulated iophenoxic acid to simulate a vaccination program. Using knowledge from the pen studies, bait uptake and factors affecting bait uptake were investigated. RESULTS: Bait-delivered iophenoxic acid led to variable and inconsistent changes in blood iodine concentrations, in contrast to pigs receiving iophenoxic acid by gavage. This precluded accurate assessment of the quantity consumed, but still allowed a conservative determination of bait uptake. Iophenoxic acid in smaller capsules was consumed readily. Increasing baiting intensity appeared to increase bait uptake by wild feral pigs, and pigs of varying sexes, ages and weights appeared equally likely to consume baits. CONCLUSIONS: Encapsulated liquids can be delivered to feral pigs within baits, should the need to vaccinate feral pigs for fertility or disease management arise. High baiting intensities may be required.