US feral swine were exposed to both avian and swine influenza A viruses

Authors

Brigitte E. Martin, Mississippi State University
Hailiang Sun, Mississippi State University
Margaret Carrel, University of IowaFollow
Fred L. Cunningham, USDA/APHIS/WS National Wildlife Research CenterFollow
John A. Baroch, USDA/APHIS/WS National Wildlife Research CenterFollow
Katie C. Hanson-Dorr, USDA/APHIS/Wildlife Services/National Wildlife Research Center
Sean G. Young, University of Arkansas for Medical Sciences
Brandon S. Schmit, USDA/APHIS/WS National Wildlife Research CenterFollow
Jacqueline M. Nolting, Ohio State UniversityFollow
Kyoung-Jin Yoon, Iowa State UniversityFollow
Mark W. Lutman, USDA/APHIS/WS National Wildlife Research CenterFollow
Kerri Pedersen, USDA APHIS Wildlife ServicesFollow
Kelly Lager, USDA-ARS
Andrew S. Bowman, Ohio State UniversityFollow
Richard D. Slemons, Ohio State UniversityFollow
David R. Smith, Mississippi State UniversityFollow
Thomas J. Deliberto, USDA/APHIS/WS National Wildlife Research CenterFollow
Xiu-Feng Wan, Mississippi State UniversityFollow

Date of this Version

2017

Citation

Appl. Environ. Microbiol. doi:10.1128/AEM.01346-17

Comments

U.S. government work.

Abstract

Influenza A viruses (IAVs) in swine can cause sporadic infections and pandemic outbreaks among humans, but how avian IAV emerges in swine is still unclear. Unlike domestic swine, feral swine are free ranging and have many opportunities for IAV exposure through contacts with various habitats and animals, including migratory waterfowl, a natural reservoir for IAVs. During 2010–2013, 8,239 serum samples were collected from feral swine across 35 US states and tested against 45 contemporary antigenic variants of avian, swine, and human IAVs; of these, 406 (4.9%) samples were IAV-antibody positive. Among 294 serum samples selected for antigenic characterization, 271 cross-reacted with ≥1 testing virus whereas the other 23 did not cross-react with any testing virus. Of the 271 IAV-positive samples, 236 cross-reacted with swine IAVs, 1 with avian IAVs, and 16 with avian and swine IAVs, indicating that feral swine were exposed to both swine and avian IAVs but predominantly to swine IAVs. Our findings suggest that feral swine could potentially be infected with both avian and swine IAVs, generating novel IAVs by hosting and reassorting IAVs from wild birds and domestic swine and facilitating adaptation of avian IAVs to other hosts, including humans, before their spillover. Continued surveillance to monitor the distribution and antigenic diversities of IAVs in feral swine is necessary to increase our understanding of the natural history of IAVs.