Bird-Brained: First Infection of US Livestock with Highly Pathogenic Avian Influenza

An electron microscope image of H5N1 HPAI viruses, similar to the strain detected in Minnesota. (CDC Public Health Image Library)

The Minnesota State Board of Animal Health announced the first US infection of a livestock animal with H5N1 Highly Pathogenic Avian Influenza (HPAI), a severe strain of bird flu, on March 11, 2024. The world has been experiencing unprecedented levels of HPAI across multiple species for over three years, with the virulent infection decimating wild birds and commercial poultry flocks.

Since 2005, over 500 million birds worldwide have died due to the disease, leading to devastating impacts on the global economy. In 2020, an outbreak swept through Kazakhstan, culling 500,000 birds, and Egypt declared a state of emergency after two outbreaks emerged dangerously close to Cairo. The WOAH stated that the current HPAI strains are particularly adept at “moving from wild birds to wild mammals, with impact beyond anything previously seen.”

Scientists found the infection in the brain tissue of goat kids that died while in quarantine after a wave of bird flu swept through ducks and chickens pastured in the same area. Minnesota State Veterinarian Brian Hoefs, DVM, stated that while the risk to the public is low, the detection of HPAI in livestock “highlights the possibility of the virus infecting other animals on farms with multiple species.” Following laboratory confirmation of the cases, the United States submitted a report to the World Organization for Animal Health.

While the current impact on human health remains low, the probability of disease transmission from animals to humans and its subsequent spread through the population is a constant possibility, especially given the virus’ ability to spread to and between wild mammals, says Foreign Affairs. Such a threat would require a swift global response to avoid another devastating pandemic.

However, the greatest threat HPAI poses remains its impact on global agricultural and food production systems. Since the onset of the current US outbreak, China has instituted bans on poultry imports, resulting in billions of dollars in lost income and raising tensions between the two nations. 

HPAI is a test case for how a post-COVID-19 global biosecurity system reacts to threats. As negotiations on a new WHO Pandemic Agreement continue, infectious disease threats such as HPAI have taken the forefront. Managing such threats will be essential to future global biosecurity and pandemic prevention efforts, especially considering the impact that 21st-century zoonotic diseases such as COVID-19, SARS, MERS, and Ebola have had on human health.

HPAI spilling over to U.S. livestock serves as a wake-up call to the impacts that avian influenza is having on our food supply, as well as the devastating possibility of a future HPAI pandemic.