Publications
Citation
Nelson MI, Stucker KM, Schobel SA, Trovão NS, Das SR, Dugan VG, Nelson SW, Sreevatsan S, Killian ML, Nolting JM, Wentworth DE, Bowman AS
Introduction, Evolution, and Dissemination of Influenza A Viruses in Exhibition Swine, USA, 2009-2013.
Journal of Virology. 2016 Sep 28;
Abstract
The swine-human interface created at agricultural fairs, along with the generation of and maintenance of influenza A virus diversity in exhibition swine, presents an ongoing threat to public health. Nucleotide sequences of influenza A virus isolates collected from exhibition swine in Ohio (n=262) and Indiana (n=103) during 2009-2013 were used to investigate viral evolution and movement within this niche sector of the swine industry. Phylogenetic and Bayesian analyses were employed to identify introductions of influenza A virus to exhibition swine and study viral population dynamics. In 2013 alone, we identified ten independent introductions of influenza A virus into Ohio and/or Indiana exhibition swine. Frequently, viruses from the same introduction were identified at multiple fairs within the region, providing evidence of rapid and widespread viral movement within the exhibition swine populations of the two states. While pigs moving fair-to-fair-to-fair is possible in some locations, the concurrent detection of nearly identical strains at several fairs indicates a viral common source was more likely. Importantly, we detected an association between the high number of human H3N2v infections in 2012 and the widespread circulation of influenza A viruses of the same genotype in exhibition swine in Ohio fairs sampled that year. The extent of viral diversity observed in exhibition swine, and the rapidity with which it disseminated across long distances, indicates that novel strains of influenza A virus will continue to emerge and spread within exhibition swine populations, presenting an ongoing threat to humans.