H5N1 Virus in Milk: Minimal Health Risk
- Recent studies have detected fragments of the H5N1 avian influenza virus in a important percentage of the US milk supply.
- Researchers have found genetic material from the H5N1 bird flu virus in approximately 20% of retail milk samples tested across the United States, according to a recent study.
- The initial detection occurred in samples collected in early April 2024, with subsequent testing confirming the widespread presence of viral fragments. The United States Department of Agriculture (USDA)...
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Bird Flu Fragments Detected in US Milk Supply: What You Need to Know (September 27, 2025)
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Recent studies have detected fragments of the H5N1 avian influenza virus in a important percentage of the US milk supply. While the findings raise concerns, scientists and regulatory agencies currently state there is no known risk to consumers due to pasteurization processes.
Last updated: September 27, 2025 at 00:45:31 PST
what Has Been Discovered?
Researchers have found genetic material from the H5N1 bird flu virus in approximately 20% of retail milk samples tested across the United States, according to a recent study. The fragments are not infectious virus particles, but rather remnants of the virus’s RNA. This indicates that dairy cows may have been infected with the virus, even if they don’t exhibit severe symptoms.
The initial detection occurred in samples collected in early April 2024, with subsequent testing confirming the widespread presence of viral fragments. The United States Department of Agriculture (USDA) began testing milk samples in April 2024 after the first confirmed cases of H5N1 in dairy cows were reported in Texas and Kansas. USDA News Release
why Isn’t This a Cause for Panic?
Health officials emphasize that the pasteurization process effectively eliminates the virus. Pasteurization heats milk to a high enough temperature to destroy any potential viral particles, rendering it safe for consumption. The centers for disease Control and Prevention (CDC) has stated that the commercial milk supply poses no known risk to consumers. CDC Avian Flu Information
The viral fragments detected are RNA, not the complete, infectious virus. RNA is a genetic blueprint,and its presence doesn’t equate to the ability to cause infection. The fragments are considered a marker of past exposure, not an active threat.
How Did the Virus Get Into the Milk Supply?
The virus is believed to have spread to dairy cows through contact with wild birds, particularly migratory waterfowl. Dairy farms in several states, including Texas, Kansas, Michigan, and Idaho, have reported cases of H5N1 in their cattle.USDA APHIS Stakeholder Update
The exact mechanism of transmission from wild birds to cows is still under investigation, but it’s thought to involve contaminated water sources, feed, or direct contact. The virus then sheds in the milk of infected cows, leading to the detection of viral fragments.
What Are the Symptoms in Cows?
Symptoms in dairy cows are generally mild and include decreased milk production, loss of appetite, and lethargy. some cows may also develop fever. The symptoms are frequently enough subtle, making detection challenging. american Veterinary Medical Association
The USDA is working with state veterinary officials to monitor dairy herds and implement biosecurity measures to prevent further spread of the virus. These measures include restricting movement of cattle and enhancing sanitation practices.