Zoonotic Influenza Infections of Swine Origin at Ohio Agricultural Fairs

The bidirectional transmission of influenza A viruses between animals and humans are clearly an important part of the complex dynamics of influenza evolution, however a thorough understanding of this process remains a mystery. The role of swine in overall human influenza evolution is unclear, but a long history of the study of swine origin influenza has revealed that influenza evolves in swine populations both in North America and Europe.

In 2009, a pandemic occurred with the emergence of the H1N1 pandemic (pdm) virus which was found to have originated from both a North American and European swine lineage, again reinforcing how viruses evolving in swine can lead to important human pathogens. Interestingly this virus was transmitted back into swine and birds in North America. In 2011, an H3N2 swine origin influenza virus known as the H3N2v and containing the H1N1pdm matrix genomic segment was reported causing human infections in multiple parts of the US. In 2012, these cases increased, especially during the summer months. Since 2011, 321 confirmed cases have been reported from 13 states including 107 cases in Ohio. Almost all of these cases have been linked to swine exposure on farms or at agricultural fairs.

Study of these zoonotic transmission events at agricultural fairs are necessary in order to better understand how and why these events occur, how human pathogens emerge, and how to potentially prevent events from occurring. These events could lead to new pandemics and epidemics so their prevention is crucial. The goal of this study is to examine rates of bidirectional zoonotic transmission at Ohio agricultural fairs. Through collection of viruses and host samples, we hope to begin to answer questions regarding how viruses cross species barriers, adapt to new hosts, and how these events could impact overall influenza virus evolution.