Evidence accumulating in 2011-2012 indicates that there is significant intra- and inter-species transmission of influenza A viruses at agricultural fairs, which has renewed interest in this unique human/swine interface. Six human cases of influenza A (H3N2) variant (H3N2v) virus infections were epidemiologically linked to swine exposure at fairs in the United States in 2011. In 2012, the number of H3N2v cases in the Midwest had exceeded 300 from early July to September, 2012. Prospective influenza A virus surveillance among pigs at Ohio fairs resulted in the detection of H3N2pM (H3N2 influenza A viruses containing the matrix (M) gene from the influenza A (H1N1) pdm09 virus). These H3N2pM viruses were temporally and spatially linked to several human H3N2v cases. Complete genomic analyses of these H3N2pM isolates demonstrated >99% nucleotide similarity to the H3N2v isolates recovered from human cases. Actions to mitigate the bidirectional interspecies transmission of influenza A virus between people and animals at agricultural fairs may be warranted.
Bibliographical noteFunding Information:
The authors wish to acknowledge the assistance of Mary DiOrio, Brian Fowler, Kathy Smith (Ohio Department of Health, USA), Tony Forshey (Ohio Department of Agriculture, USA) and Sabrina Swenson (United States Department of Agriculture, USA) for support during the investigation. This work has been funded by the Minnesota Center of Excellence for Influenza Research and Surveillance with federal funds from the Centers of Excellence for Influenza Research and Surveillance, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under contract NO. HHSN266200700007C and the USDA/ APHIS NVSL. Any mention of trade names or commercial products is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the US Department of Agriculture.
Copyright 2014 Elsevier B.V., All rights reserved.
- human H3N2v