A comprehensive review by Dr. Jason Lombard and his co-authors makes it clear. They stress that knowledge of H5N1 transmission is crucial to halt its spread in the dairy sector. While the underlying patterns have continued, this outbreak is a historic challenge. It’s the first infectious disease of this scale to affect the U.S. dairy industry in almost a hundred years. The review does an excellent job at outlining these complicated interactions between H5N1’s transmission. These dynamics have been exacerbated by the complex organization of the dairy industry, which increases interactions between cattle, humans, and other species.
Dr. Chloe Stenkamp-Strahm, DVM, Ph.D., stresses that the first infected dairy farm likely acquired H5N1 from emergent wild bird reservoirs. This makes wildlife a key player in the virus’s transmission. As Dr. Lombard described the current outbreak as unprecedented, it has a truly remarkable ability to spread between farms and within herds. According to Dr. Cherissa Abdul-Hamid, DVM, MPH, DACVPM, there have now been 70 confirmed cases tied to this outbreak. Nearly all of these cases are among those who handle cattle and poultry on a daily basis.
To that end, the review provides critical insight into the complexity of H5N1 transmission dynamics and its far-reaching impact. It urges a One Health approach, one that acknowledges the connection between animal health, human health, and environmental factors. This is an important perspective to have. The concern of H5N1 mutating into a viral strain that can spread from human to human highlights the very real possibility of future pandemics. Dr. Carol Cardona, DVM, Ph.D., warns that failing to control the virus could enhance its ability to spread among humans.
From its introduction into U.S. dairy cattle, the H5N1 outbreak has affected all aspects of the dairy supply network. As a veterinarian-turned-ecologist, Dr. Brian McCluskey, DVM, Ph.D., emphasizes the need to view large-scale dairy operations as ecosystems in which different health factors can interact. Our systematic review provides producers, veterinarians, and policymakers with evidence to help guide their decision-making. It further illustrates why embracing a One Health approach is so important for addressing the broader challenges posed by H5N1.
Three key recommendations emerge from a recent RAND article on this issue: declare H5N1 a public health emergency, mandate ongoing nationwide testing of representative samples of dairy and beef cattle, and enhance collaboration among stakeholders in animal health and public health sectors. To address these growing risks, these measures not only provide critical funding, but seek to encourage proactive responses to the rapidly changing landscape.