RNA Reports Bird Flu Virus Has Been Spreading in the US: Is Eggs and Milk Safe?

• Bird flu (H5N1) has spread among wild birds and poultry farms in the US.
• The virus has been found in milk samples but pasteurisation process kills the virus and supermarket milk is safe.
• Experts recommend avoiding unpasteurized milk and egg products.

In early December, Sonoma County, California, declared an agricultural disaster when two poultry farms had to cull their entire flocks to contain the spread of “highly pathogenic avian influenza” or bird flu. The specific strain, H5N1, first surfaced in the US in early 2022, leading to alarming reports across the country: Two zoos reported bird flu among their birds, prompting zoos nationwide to withdraw their avian displays; in Georgia, three bald eagles succumbed to the virus; and hundreds of infected birds were found dead near a lake in the Chicago suburbs.

Since then, tens of millions of turkeys and chickens at commercial farms have been euthanized to stem the outbreak’s tide.

Amidst already rising inflation rates, the cost of eggs surged alongside avian influenza cases. According to the University of Arkansas System Division of Agriculture, bird flu was a major factor behind elevated egg prices in 2023, peaking at $4.82 per dozen in January (recently, they have stabilised around $2.99 per dozen).

However, on a late Thursday, the Food and Drug Administration (FDA) made a concerning announcement: One in five commercial milk samples tested in a nationwide survey contained traces of the H5N1 virus, suggesting a wider spread in dairies than previously believed, as per Reuters.

With these developments, the safety of egg and dairy products comes into question for home cooks. Let’s explore the current situation and its implications.

What Is Bird Flu?

Avian influenza, or bird flu, is a virus naturally found among wild aquatic birds worldwide, according to the Centers for Disease Control and Prevention (CDC). Initially identified in Italy in the late 19th century, it was initially confused with a form of fowl cholera and dubbed “fowl plague.” The term “bird flu” gained prominence in the 20th and 21st centuries with the emergence of highly pathogenic strains like H5N1 and H7N9.

While bird flu viruses typically do not infect humans, sporadic human infections have occurred, notably with the current strain, H5N1. Recently, a Texas dairy farm worker exposed to cattle tested positive for H5N1, displaying only eye redness, consistent with conjunctivitis, as the sole symptom, and is recovering.

This incident marks the second human case in the US during this wave of the disease. The first, in 2022, involved a person directly exposed to poultry while culling (depopulating) poultry with presumptive H5N1 bird flu in Colorado.

Though rare, bird flu can transmit to other mammals, including cattle. Currently, nine states — North Carolina, Ohio, Michigan, Texas, New Mexico, Colorado, Kansas, South Dakota, and Idaho — have reported bird flu outbreaks among cattle, impacting an estimated 34 herds as of Friday. Cattle could have become infected through direct contact with infected birds, living in contaminated environments, or consuming feed containing contaminated poultry by-products or droppings.

Are Supermarket Eggs and Milk Safe?

The FDA recently reported that samples of pasteurised milk tested positive for remnants of bird flu, clarifying that these materials were inactivated and not a risk to consumers.

Dr. Scott Roberts, an Infectious Disease specialist at Yale New Haven Hospital, and assistant professor at Yale School of Medicine, emphasised the low risk of transmission through supermarket eggs and milk. The pasteurisation process effectively eliminates any viable virus, further ensuring safety.

The FDA reiterated this stance in a statement after receiving additional results from their national commercial milk sampling study in coordination with USDA, confirming that pasteurization effectively inactivates HPAI (avian influenza). No live, infectious virus was detected in the samples, affirming the safety of the commercial milk supply.

Experts recommend avoiding unpasteurized or raw milk and egg products to minimise risk.

What’s Next?

The USDA announced that every lactating cow must now be tested and receive a negative result before being moved to a new state. This measure aims to track the disease and understand its spread better. Michael Watson, an administrator with the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, stated that they could conduct tens of thousands of tests daily.

Additionally, the FDA will continue assessing retail samples from its study of 297 samples of retail dairy products from 38 states. All samples with a PCR positive result are undergoing egg inoculation tests to determine the presence of infectious virus. These efforts will provide crucial information for further reviewing the safety of pasteurisation against the virus and confirming the safety of the commercial milk supply.

In conclusion, while bird flu has presented challenges, rigorous testing, pasteurisation processes, and preventive measures are in place to ensure the safety of dairy and egg products in the US.

Tags: Bird flu, H5N1, avian influenza, dairy products safety, pasteurisation effectiveness, FDA announcement, USDA testing, poultry farms, commercial milk, CDC guidelines.