Episode Twenty-Four: Latest Updates on HPAI H5N1 and Dairy—What We Know Today About Bird Flu Viral Dynamics and Pathways with Diego Diel, DVM, PhD
Since our last episode devoted to the highly pathogenic avian influenza (HPAI) H5N1 outbreak in US dairy herds, the virus has passed some concerning new milestones—infecting over 900 herds, more than 60 people (including 1 death), and millions of domestic poultry flocks—and continues to present a pressing concern to dairy scientists and the dairy sector as a whole. To help our listeners keep their finger on the latest science, Matt sits down with Diego Diel, DVM, MS, PhD, a leading virologist and associate professor in the Department of Population Medicine and Diagnostic Sciences at Cornell University’s College of Veterinary Medicine. Diego and his lab team at Cornell were on the testing frontlines during the COVID-19 outbreak and are once again leading the charge in studying, documenting, and understanding H5N1—including via three impactful recent publications in JDS Communications and Nature. He and Matt unpack the complexities of the H5N1 virus, explaining its unique components and genetic lineage, how it affects different cells across species, and tracking its evolution from wild birds to spreading in dairy cattle and spillovers to other avian and mammal hosts. The two discuss Diego’s recent work experimentally infecting dairy cows and calves to better understand the dynamics of the virus, detailing how it impacts the mammary gland, leading to severe mastitis and surprisingly high viral loads in milk. They review some of the remaining unknowns of the outbreak: Why haven’t we seen H5N1 in beef cattle? How is the virus spreading regionally from farm to farm? What is the exact route of infection for dairy cows? Will vaccines be needed to stop its spread? The duo also cautiously explores the pandemic potential from the outbreak, outlining the current presentation of the virus in humans and clarifying that there is currently no human-to-human transmission. Thankfully, we have tools—such as antivirals that are effective against influenza in humans—in the toolbox to fight a pandemic if the virus were to mutate. While reassuring listeners that current data suggest a low risk, Diego emphasizes the importance of continued surveillance, testing, preventive measures, and research to understand how H5N1 might evolve.
This episode of Dairy Digressions is a must-listen for anyone in the dairy sector seeking a comprehensive understanding of what we know today about the H5N1 outbreak.
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