Poster Presentation 64th International Conference of the Wildlife Disease Association 2015

Influenza A exposure in feral swine of South Australia. (#104)

Antonia E Dalziel 1 , Phillip Cassey 1
  1. University of Adelaide, Adelaide, SA, Australia

Wild waterfowl are known to be the main reservoir for circulating avian influenza viruses (AIV) with spillover into domestic poultry occurring infrequently. In the southern hemisphere, the breeding season and habits of wild waterfowl are not as predictable as in the north, and the dynamics which perpetuate AIV in populations continues to be investigated. Other wild animals, which share their environment, are also subject to exposure to influenza viruses. In Asia and North America, pigs have been found to be a suitable mixing vessel for influenza viruses, with occasional viral spillback into waterfowl. The exposure of feral pigs to AIV has not been investigated in Australia to date, and the extensive population and distribution of feral pigs in wetland areas, sharing habitats with waterfowl creates an opportunity for exposure and infection. Blood samples for serology and nasal swabs for virus identification were obtained from the carcasses of 23 feral pigs shot as part of a State government control cull around two Ramsar wetlands in South Australia, Kingston SE in the south-east of the state, and Innamincka in the north-east corner. The serum samples were analysed using the IDEXX Influenza A Antibody Test Kit (Netherlands). Three of the 23 samples tested positive for influenza A antibodies, indicating that the feral pigs had been exposed to influenza A across both sites. We propose that feral pigs in these habitats are frequently exposed and could present an appropriate mixing vessel for new strains of AIV.With both avian and swine influenza being notifiable diseases in Australia and worldwide, surveillance methods utilising available species and focusing limited resources by cooperation between agencies could provide a viable adjunctive method of monitoring incursions of disease.