Bird Flu Outbreak Spreads to Dairy Cows in U.S. States

The highly pathogenic H5N1 avian influenza virus has extended to dairy cows in 9 U.S. states, infecting over 90 million chickens, 9,000 wild birds, 34 dairy herds, and 2 people since 2022, according to the U.S. Department of Agriculture (USDA). The outbreak, which was first detected in a Colorado dairy herd on April 26 has raised concerns about the virus potentially spreading to humans through the nation's milk supply.

The virus has been particularly devastating for poultry flocks, leading to widespread deaths or culling. It has also been detected in other mammals like seals, foxes, raccoons, and skunks. While the risk to most Americans is considered low, public health experts are concerned about the virus's potential to mutate and transmit more easily from animals to humans, triggering another deadly viral outbreak like COVID-19.

Why this matters: The H5N1 outbreak in dairy cows marks a significant development in the virus's ability to infect mammals, increasing the potential for it to adapt and spread to humans. As the virus reaches an important point of human-animal convergence on dairy farms, the regular interactions between people and infected cows and their milk provide opportunities for the virus to evolve, posing a serious public health threat.

The USDA has confirmed infections in dairy herds across 6 states, with the initial cases in Texas and Kansas likely introduced by wild birds. The virus has since spread to additional herds in Kansas, New Mexico, Ohio, Idaho, and Michigan. While transmission between cows cannot be ruled out, the spread to an increasing number of species and wider geographic reach have raised concerns about the possibility of human infection.

Two human cases have been reported in the U.S., both among farm workers who handled sick animals. The latest case in Texas is believed to have contracted the virus from a cow, marking the first instance of the virus being detected in a cow. The CDC notes that human infections are rare but can result in severe symptoms, and that the virus is very unlikely to spread through properly cooked poultry and eggs.

The USDA is conducting studies to test ground beef and beef muscle samples for the presence of the virus, and is also conducting a cooking study to determine how much of the virus remains after cooking. While the meat supply is considered safe, the USDA recommends proper handling and cooking of raw meats. Milk production has been impacted, but agencies say the loss is limited, and they encourage consumption of pasteurized dairy products.

Experts warn that the U.S. is repeating the mistakes of the COVID-19 pandemic, failing to prioritize high-risk groups and lacking data transparency.

Key Takeaways

• H5N1 avian flu has spread to dairy cows in 9 U.S. states, infecting over 90M chickens.
• The virus has been detected in other mammals, raising concerns about potential human transmission.
• Two human cases have been reported, with the latest case linked to a cow.
• The USDA is testing meat and milk supplies, but recommends proper handling and cooking.
• Experts warn the U.S. is repeating COVID-19 mistakes, with a slow federal response.