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The Value of Flu Surveillance in Swine

Just this week, a research study was published in the Proceedings of the National Academy of Sciences entitled "Prevalent Eurasian avian-like H1N1 swine influenza virus with 2009 pandemic viral genes facilitating human infection." The study, covering samples collected in 2011-2018, highlights the identification of an influenza strain prominent in swine in China. The authors’ interpretation of the findings raised interest among those in the swine industry and the media regarding any possible implications to the human population. Thanks to the USDA’s Influenza A Virus in Swine Surveillance program, the U.S. swine industry has much more information available to analyze the significance of influenza-related research or diagnostic findings than was available during the H1N1 influenza pandemic in 2009. Having the surveillance program in place has allowed us to work with USDA and CDC to provide a perspective on the impact of this virus on the U.S. swine and human population.

The USDA, using funds provided by the U.S. Centers for Disease Control and Prevention, initiated the surveillance program in 2010. The program utilizes diagnostic samples collected from case-compatible swine accessions, swine exhibiting influenza-like illness at points of concentration, and swine linked to confirmed human cases of influenza. These samples are then analyzed to identify individual influenza strains. Any positive findings are submitted to GenBank so they are available for human and animal researchers to further analyze and evaluate. The value of this program relies heavily on samples submitted by veterinarians and producers.

Since 2011, almost 175,000 samples have been submitted to the program resulting in approximately 6200 virus isolates being placed in the repository. Because of this program, we can say with relative confidence that this Eurasian avian-like H1N1 virus is not present in the U.S. swine herd and it has contributed to the presence of a candidate vaccine virus that would provide protection against this virus were it to be introduced. The program also serves as an early warning system to aid in the detection of an emerging or modified influenza virus.

So, thanks to all of you that continue to submit tissues for diagnostic testing for respiratory diseases. It’s important that we continue to support the program. If you do not currently submit tissues for respiratory disease diagnosis, consider doing so. There are areas of the country where we get relatively few submissions. The value of this program would be even further enhanced if we can obtain additional tissues from some of these underrepresented areas.