As of Monday, April 8, 2024, the U.S. Department of Agriculture (USDA) has confirmed highly pathogenic avian influenza (HPAI) in dairy herds in Idaho, Kansas, Michigan, New Mexico, Ohio and Texas. The confirmations were made via milk samples as well as nasal swabs and viral genome sequencing of the affected herds. USDA is conducting similar tests in other states.
The U.S. Centers for Disease Control and Prevention (CDC) confirmed that a person in the United States has tested positive for the highly pathogenic avian influenza (HPAI) (H5N1) virus, as reported by the Texas Department of Health and Human Services. According to the CDC, the person had exposure to dairy cattle in Texas presumed to be infected with HPAI. The patient reported eye redness (consistent with conjunctivitis), as their only symptom, and is recovering. The patient was told to isolate and is being treated with an antiviral drug for flu.
USDA confirmed that the detections appear to have been introduced by wild birds; however, the Department continues to conduct an epidemiological investigation into how the virus is being spread among dairy herds and, so far, has no conclusive evidence. In the meantime, USDA strongly recommends limited or cautious movement of cattle, testing before moving cattle, and quarantining cattle upon arrival at their destination.
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. 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 latest news and resources from the coordinated U.S. government response to the illness is available here.
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 influenza viruses inclusive of HPAI. Dr. Sam Alcaine, Associate Professor of Food Science at Cornell University, states, “Several studies have demonstrated that influenza viruses, including HPAIV, are inactivated by heat. The legally required temperature and time requirements for milk pasteurization will readily inactivate HPAIV.”
Moreover, the federal PMO prohibits milk from sick cows from entering the food supply chain. Sick or affected dairy cows are segregated on farms, as is normal practice with any animal health concern, and their milk does not enter the food supply. Additionally, USDA and FDA remind consumers that raw milk should not be consumed regardless of its availability. Raw milk is a key vehicle in the transmission of human pathogens, including E. coli O157:H7, Campylobacter, Listeria monocytogenes, and Salmonella, among others. As this situation continues to evolve, IDFA joins the USDA and FDA in strongly recommending that all raw milk and raw milk components be heat treated to a temperature and duration that kills harmful pathogenic bacteria and other microorganisms, including viruses inclusive of HPAI, regardless of the product’s intended use for human or animal consumption. FDA also recommends out of an abundance of caution that milk from cows in an affected herd not be used to produce raw milk cheeses.
More information from FDA can be found here.
Trade and Exports
IDFA is working with federal partners to ensure trading partners rely on the OIE-acknowledged, science-based food safety steps taken in U.S. dairy processing to preserve market access. There are no known disruptions or barriers to U.S. dairy trade and exports at this time.
About the Illness in Cows
Dairy producers with affected cows are reporting a rapid onset illness in herds, specifically among older, lactating cows. Clinical signs include:
- Decreased herd level milk production
- Acute sudden drop in production
- Decrease in feed consumption
- Abnormal feces and some fever
- Older cows are more likely to be impacted than younger cows
According to dairy farmers and veterinarians reporting on affected herds, most affected cows recover within 10 days to three weeks.
Dairy farmers who observe clinical signs in their herd should immediately contact their veterinarian. Veterinarians who observe these clinical signs and have ruled out other diagnoses on a client’s farm should contact the state veterinarian and plan to submit a complete set of samples to be tested at a diagnostic laboratory. USDA has told the dairy community and practitioners that cattle are expected to fully recover in a few weeks and there is no need to cull dairy cows because HPAI poses a low risk to human health. While HPAI is fatal in about 90-100 percent of chickens, according to the CDC, there has been little to no mortality reported in dairy cows. Cows recover in about two weeks. Moreover, there are no widespread impacts on dairy production today. USDA will continue to share information as they learn more.
Enhanced Biosecurity Protocols Necessary on U.S. Dairy Farms
Dairy farmers must implement enhanced biosecurity protocols on their farms, limiting the amount of traffic into and out of their properties and restricting visits to employees and essential personnel. Avian influenza is an animal health issue, and the risk to humans remains low. However, as USDA advises, people with close or prolonged, unprotected exposures to infected birds or other animals (including livestock), or to environments contaminated by infected birds or other animals, are at greater risk of infection.
HPAI is transmitted through droppings or nasal discharge of infected birds, which can contaminate water, feed, dust, and soil. The virus may also be spread by wind. People can carry the virus on their shoes, clothes, equipment, and vehicles.
As a precaution, dairy farmers must take important steps to protect their operations and the milk supply. When handling any sick animal, people should take basic precautions to protect themselves. Wear gloves, avoid touching their eyes, nose, and mouth until washing their hands, remove clothing worn around sick animals to be washed, and shower at the end of the day.
The National Dairy FARM Program (NDFP) through the National Milk Producers Federation offers several valuable biosecurity resources as does USDA’s Animal and Plant Health Inspection Service (APHIS).
What is Avian Influenza?
While it is uncommon for Highly Pathogenic Avian Influenza to affect dairy cows, USDA APHIS has been tracking detections of HPAI in mammals for many years in the United States, leading dairy farmers and veterinarians in the United States to prepare for this eventuality.
Initial testing by the National Veterinary Services Laboratories has not found changes to the HPAI virus in dairy cattle that would make it more transmissible to humans. The risk to humans remains low. For more information about HPAI, visit the website of the American Veterinary Medical Association, or AVMA.
Government & Industry Resources
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