Swine industry responds to H5N1 outbreak in dairy cattle

Pork industry no stranger to managing new, novel influenza strains.

July 8, 2024

7 Min Read
National Pork Board

A multistate outbreak of highly pathogenic avian influenza Type A (H5N1) in dairy cows began on March 25 in Texas. The cross-species outbreak immediately drew the attention of pork industry organizations whose representatives began collaborating for a cohesive, coordinated - not duplicative – effort to be informed, engaged and responsive on behalf of the pig farmers and practitioners they represent and serve.

“Since H5N1 was identified in dairy cattle, there’s been constant collaboration and communication between partners in the pork industry. The Pork Board has been meeting at least weekly with stakeholders from the Swine Health Information Center, the American Association of Swine Veterinarians, The Meat Institute, the National Pork Producers Council, the USDA and others to closely monitor H5N1 updates and response within the dairy industry. These meetings give us the opportunity to discuss the potential implications and possible response,” remarked Marisa Rotolo, veterinary epidemiologist, director of swine health, National Pork Board.

As of July 7, H5N1 has been confirmed in dairy cattle in 12 states. This includes 28 herds in Idaho, 25 in Michigan, 27 in Colorado, 21 in Texas, 12 in Iowa, eight in New Mexico, seven in Minnesota, five in South Dakota, four in Kansas and one each in North Carolina, Ohio and Wyoming, per USDA’s Animal and Plant Health Inspection Service. H5N1 has not been found in pigs.

In an opinion piece by U.S. Secretary of Agriculture Tom Vilsack titled, "Good Biosecurity Is the Key to Mitigating the Spread of H5N1," released on June 26, he wrote, “The more we learn about H5N1, the more we understand that good biosecurity is a critically important path to containing the virus. Containing, and eliminating, the virus in our dairy cattle is essential – to protect the health of our herds and flocks, our farmers, our farmworkers, our families and the rural economy they make possible.” Pork industry representatives support efforts being made by the dairy and poultry sectors, while looking for lessons in their experience to apply in the event it is needed for pigs.

Collaboration is critical

Collaboration is critical for preparedness and response, not only with other pork organizations, but within the barnyard and beyond. “We have those relationships in place and communicate almost daily with our colleagues in other pork organizations, and frequently with those working in animal health, human health and the regulatory space,” said Abbey Canon, DVM, MPH, DACVPM, director of public health and communications with the American Association of Swine Veterinarians.

Part of AASV's mission is to increase the knowledge of swine veterinarians, protect and promote the health and well-being of pigs, and advocate for science-based approaches to veterinary, industry and public health issues. Canon says the organization strives to disseminate the most up-to-date information that swine veterinarians need and can use or distribute to their clients.

Leveraging lessons learned

Preparing for and responding to livelihood-damaging endemic and emerging swine disease, including influenza, is nothing new for the pork industry. “The pork industry is not a stranger to managing new and novel influenza strains. We learned a lot from H1N1 in 2009, which resulted in a lot of good planning between industry stakeholders and federal and state government agencies which can serve as the foundation for a measured and appropriate response to the introduction of different strains in the future,” remarked Patrick Webb, assistant chief veterinarian, National Pork Board.

Existing preparedness programs developed for the swine industry serve multiple purposes. “While the swine industry has had a particular focus on African swine fever and other foreign diseases, much of this work and preparation benefits current conversations about H5N1. Examples include enhanced biosecurity protocols as part of the Secure Pork Supply plan, development of the Certified Swine Sample Collector program to improve our surveillance capacity, and improvements to live swine traceability with the swine traceability standards supported by producers at National Pork Forum. The industry recognizes that there are multiple threats to swine health and in response, has invested time, money and resources into improving our readiness,” explained Anna Forseth, DVM, MS, director of animal health, National Pork Producers Council.

“The swine industry has been monitoring the evolving H5N1 situation closely. We know that new or novel strains of a virus can raise questions and activity beyond how it impacts the animals themselves, including regulatory action and impacts to trade. As we watch the dairy industry’s experience, we are engaging in conversations with state and federal regulators, public health officials, diagnostic laboratories and trading partners to educate decision makers about the swine industry,” Forseth said.

Informing pork industry’s preparedness, response

The Swine Health Information Center was founded in 2015, after the porcine epidemic diarrhea virus outbreak of 2013 when resources and response were determined to be inadequate. Resulting work of the center has informed the industry’s response, preparation and preparedness efforts surrounding emerging disease issues, including H5N1.

“The recent detection of HPAI in domestic livestock raised questions regarding the emerging threat and potential risks for swine herds. The Swine Health Information Center, along with the American Association of Swine Veterinarians, hosted a webinar April 19, 2024, on influenza A viruses, with the goal of informing producers about influenza A virus pathogenesis, distribution, surveillance and research including the H5N1 outbreak. The webinar highlighted practical steps producers could take to reduce the risk of avian influenza on their farms, with a focus on biosecurity considerations to decrease wild bird access, and outlined the outbreak investigation tools available through SHIC for use during suspected health challenges,” explained Megan Niederwerder, DVM, PhD, executive director of SHIC.

SHIC provides additional tools for practitioners and producers to employ in preparedness efforts as well. “Swine producers and their veterinarians are very familiar with surveillance and management of influenza A viruses in their herds and the detection of H5N1 in dairy cattle highlights the continued importance for IAV surveillance. The Swine Disease Reporting System, funded by SHIC, provides information and tools that can be applied for use in decision making on farms. Monthly domestic disease monitoring reports detail the detection of influenza A virus across six veterinary diagnostic laboratories and represent >96% of U.S. swine sample submissions, enabling producers to rapidly detect new viruses, track changes over time and by region, and inform decisions for management strategies,” stated Lisa Becton, DVM, MS, DACVPM, associate director of SHIC.

One Health perspective incorporated

Influenza has indeed been present in the U.S. swine industry for decades with multiple strains impacting herds. "AASV recommends pork producers, swine veterinarians and diagnostic laboratories actively participate in IAV surveillance programs that provide information regarding influenza A virus evolution and epidemiology. Participation in these surveillance programs can help identify and quickly respond to emerging threats with early detection,” stated Canon. “Further, AASV supports the recommendation that people working with swine take all available precautions, including vaccination (with their human health professional’s approval), biosecurity and personal protection measures to work towards prevention of bidirectional influenza transmission. It is important to consider cross-species transmission of influenza viruses as part of a One Health approach."

Following the discovery of H5N1 in dairy herds, four human cases of the influenza strain have been detected in people, per the U.S. Centers for Disease Control and Prevention. “This is a great reminder for the industry of how important our seasonal flu shots are. Since pigs can contract influenza strains from humans, keeping workers healthy also keeps pigs healthy. Everyone who works with pigs should be getting their annual flu shot,” commented Heather Fowler, public health veterinarian, director of producer and public health, National Pork Board

Preparing for outbreak together

“The current influenza outbreak is a great example of how important a One Health approach is when dealing with illnesses that affect both humans and animals in a shared environment. Since the identification of the H5N1 virus in dairy cattle, the Pork Board has been working collaboratively with partners across the barnyard to help us prepare if we were to have an introduction of H5N1 into the swine herd,” said Fowler.

“The swine industry already has extensive knowledge and experience when it comes to flu management and monitoring. We have multiple programs that can be quickly deployed should H5N1 be detected in swine,” Rotolo observed. Existing programs combined with intentional preparedness efforts equip the pork industry to deploy an effective response to H5N1 in the U.S. swine herd if needed.

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