Recent U.S. Department of Agriculture (USDA) tests have identified particles of the highly pathogenic avian influenza A, also known as H5N1 or bird flu, in tissue samples from a dairy cow. This alarming finding marks a rare instance of bird flu detection in a non-avian species, underscoring potential new risks for animal health and food safety.
The infected cow was part of a group of 109 cattle designated for culling due to systemic diseases at a slaughterhouse. Upon detailed inspection and subsequent testing of 96 cows, this was the only instance where the bird flu virus was identified. The USDA quickly acted to stop the tainted meat from getting into the food supply chain, strengthening the United States’ strict food safety rules.
Officials are actively tracing the origins of the infected cow and collaborating with its previous owner to uncover how the infection spread, which remains unclear. This incident arises amid increasing reports of bird flu impacting cattle populations. Since late 2023, more than 58 herds across nine states have reported infections.
The United States Department of Agriculture (USDA) and the U.S. Food and Drug Administration (FDA) have taken prompt and proactive measures to address public concerns regarding recent developments. Comprehensive tests conducted on ground beef from the affected states have consistently yielded negative results for the virus, providing assurance of the safety of this food product.
In addition, the FDA has provided explicit confirmation that pasteurized milk remains safe for consumption, further alleviating any potential worries. These reassuring outcomes are complemented by the results of a comprehensive study, which strongly suggests that thoroughly cooking beef to a minimum temperature of 145 degrees Fahrenheit effectively eliminates the virus.
However, recent research from the University of Wisconsin–Madison has revealed a new dimension to the threat. It found that raw milk from infected cows retained high levels of the virus even after five weeks. Although pasteurization at 145 degrees for five minutes rendered the virus undetectable, the standard flash pasteurization technique—181 degrees for 15 seconds—did not guarantee the same safety level. The findings indicate a significant risk associated with consuming raw milk from infected animals.
The researchers extended their study to include experiments in which mice were fed milk contaminated with the bird flu virus. After four days, the mice showed high levels of the virus in their respiratory organs before being euthanized. The study suggests a credible pathway for transmitting the virus through raw milk, posing a direct threat to public health and domestic animals.
The detection of bird flu in a dairy cow and its potential transmission through milk is a pointed reminder of the interconnectedness of animal health and human health. While H5N1 primarily affects birds, its jump to cattle and the subsequent infections in humans through direct contact raises the specter of a possible pandemic if the virus mutates to become more transmissible among humans.
Public health officials, including those from the CDC, stress the importance of constant vigilance and comprehensive surveillance to manage and mitigate the risks of new influenza viruses. The global spread of H5N1 in birds and its sporadic human infections necessitate ongoing research and preparedness to address these complex challenges.
These findings underscore the risks associated with consuming raw or inadequately processed animal products during outbreaks, prompting calls for heightened caution among consumers and regulatory bodies.
The recent identification of avian flu in a dairy cow in the United States underscores the critical need for rigorous food safety protocols and the advancement of scientific research. This serves as a reminder of the constant vigilance required to safeguard the food supply and public health.
