HPAI in Dairy Cattle

U.S. Department of Agriculture (USDA) has confirmed highly pathogenic avian influenza (HPAI) in dairy herds in nineteen states. The confirmations were made via milk samples as well as nasal swabs and viral genome sequencing of the affected herds. USDA confirmed that the detections in dairy cows appear to have been introduced by wild birds; however, the Department continues to conduct an epidemiological investigation into how the virus is being transmitted among dairy herds and, so far, has no conclusive evidence. The latest USDA report on disease spread between dairy cattle farms found multiple direct and indirect transmission routes.

The USDA, CDC, and FDA continue to affirm that milk and dairy products remain safe to consume and the threat to the public remains low. The FDA and USDA co-signed letters to dairy processors and retailers emphasizing the confidence that the U.S. government has that pasteurization is effective in inactivating H5N1 in raw milk just as it is for pathogens against which we began pasteurizing raw milk 100 years ago. Pasteurization (high heat treatment) kills harmful pathogenic bacteria and other microorganisms, including viruses inclusive of HPAI. Routine testing and well-established protocols for U.S. dairy also continue to ensure that only safe milk enters the food supply.

The U.S. Centers for Disease Control and Prevention (CDC) has confirmed 41 human cases of HPAI virus infection with an exposure source of dairy cattle in the United States in 2024 and 2025.

The latest news and resources from the coordinated U.S. government response to the illness is available here. More information related to milk and dairy safety, the virus, U.S. dairy biosecurity measures, workplace safety and protection, customer messaging, and more is located below.

Milk and Dairy Safety

According to federal officials, there are no expected impacts on the nation’s dairy supply at this time due to overlapping safeguards in place by U.S. dairy. Dairy markets and prices have been relatively unaffected to date. Consumers in the United States and around the world can remain confident in the safety and quality of U.S. dairy.

Pasteurization per the federal Grade “A” Pasteurized Milk Ordinance (PMO) kills harmful pathogenic bacteria and other microorganisms, including HPAI and other viruses. In April and May 2024, the FDA began releasing testing data affirming the effectiveness of pasteurization in destroying HPAI in retail milk and dairy samples. In August, FDA announced the results from the agency’s second survey of retail dairy products, which found all 167 samples to be negative for viable H5N1 virus. The data cited by FDA is consistent with many other studies demonstrating that the legally required temperature and time for milk pasteurization will readily inactivate HPAI. Viral fragments detected after pasteurization are nothing more than evidence that the virus is inactivated; they have zero impact on human health.