HPAI Response & Resource Center
Updated 5.3.24
WCMA members with questions may contact WCMA Executive Director John Umhoefer or WCMA Senior Director of Programs & Policy Rebekah Sweeney.
HPAI & RECENT OUTBREAK IN DAIRY HERDS
Highly pathogenic avian influenza (HPAI) is now widespread among wild birds in the U.S. and globally. The virus, also referred to as H5N1, has also caused outbreaks in commercial and backyard poultry flocks, and sporadic infections in mammals.
HPAI (H5N1) in dairy cows was first reported by the U.S. Department of Agriculture (USDA) on March 25, 2024. Unpasteurized milk from sick cattle collected from two dairy farms in Kansas and one in Texas, as well as a throat swab from a cow in another dairy in Texas, tested positive.
Outbreaks of HPAI (H5N1) have now been confirmed in dairy herds located in nine states: Colorado, Idaho, Kansas, Michigan, New Mexico, North Carolina, Ohio, South Dakota, and Texas.
USDA’s Animal and Plant Health Inspection Service (APHIS) notes, at this stage, no anticipation of a need to depopulate dairy herds. Unlike HPAI (H5N1) in birds which is typically fatal, little to no mortality has been reported among dairy cows and the affected animals are reportedly recovering while being isolated from other animals.
H5N1 symptoms in dairy cattle can include any of the following: a sudden drop in milk production; production of thicker, more concentrated, colostrum-like milk; drop in feed consumption with a simultaneous drop in rumen function; loose feces and some fever; pneumonia and mastitis.
Officials are strongly advising dairy producers to use all standard biosecurity measures, noting the importance for producers to clean and disinfect all livestock watering devices and isolate drinking water that could be contaminated by waterfowl.
Beginning April 29, USDA has also required, via Federal Order, the following:
Mandatory Testing for Interstate Movement of Dairy Cattle
Prior to interstate movement, dairy cattle are required to receive a negative test for Influenza A virus at an approved National Animal Health Laboratory Network (NAHLN) laboratory. Owners of herds in which dairy cattle test positive for interstate movement will be required to provide epidemiological information, including animal movement tracing. Dairy cattle moving interstate must adhere to conditions specified by APHIS. Note: These steps will be immediately required for lactating dairy cattle, while these requirements for other classes of dairy cattle will be based on scientific factors concerning the virus and its evolving risk profile.
Mandatory Reporting
Laboratories and state veterinarians must report positive Influenza A nucleic acid detection diagnostic results (e.g. PCR or genetic sequencing) in livestock to USDA APHIS. Laboratories and state veterinarians must report positive Influenza A serology diagnostic results in livestock to USDA APHIS.
Related guidance is available online.
Producers with concerns should reach out to their veterinarian, State Animal Health Official, and/or Area Veterinarian in Charge.
ZOONOTIC TRANSMISSION TO HUMANS
On April 1, the Centers for Disease Control and Prevention (CDC) reported a person in the U.S. has tested positive for H5N1 following exposure to dairy cattle in Texas infected with the virus. 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.
This is the second person reported to have tested positive for H5N1; a previous human case occurred in 2022 in Colorado, following the individual’s close contact with infected poultry. The person reported fatigue as their only symptom and recovered following treatment with an antiviral drug.
The CDC human health risk assessment for H5N1 for the U.S. general population remains low. However, people with close or prolonged, unprotected exposures to infected animals are at greater risk of infection.
PREVENTION MEASURES – DIRECT CONTACT
According to CDC’s interim recommendations, people should avoid unprotected exposures to sick or dead animals including wild birds, poultry, other domesticated birds, and other wild or domesticated animals (including cattle), as well as with animal carcasses, raw milk, feces, litter, or materials contaminated by birds or other animals with confirmed or suspected HPAI (H5N1) virus infection.
Farmers should also note CDC recommendations specific to their operations:
Farmers, workers, and responders should wear recommended personal protective equipment (PPE) such as an N95 filtering facepiece respirator, eye protection, and gloves, and perform thorough hand washing after contact with a sick or dead animal, feces or litter from potential infected animals.
Workers should receive training on and demonstrate an understanding of when to use PPE; what PPE is necessary; how to properly put on, use, take off, dispose of, and maintain PPE; and PPE limitations.
Employers subject to Occupational Safety and Health Administration (OSHA) regulations should comply with applicable standards as highlighted on the OSHA Avian Influenza – Standards page.
Any people exposed to birds or other animals with confirmed or suspected HPAI (H5N1) virus infection should be monitored for any signs and symptoms of illness for 10 days after the last known exposure, including people wearing recommended PPE.
PREVENTION MEASURES – FOOD RECOMMENDATIONS
According to FDA and USDA, the commercial milk supply is safe because products are pasteurized before entering the market. In new research highlighted on April 23, FDA officials noted, “We have seen nothing that would change our assessment that the commercial milk supply is safe.” FDA notes pasteurization is “not expected to remove the presence of viral particles,” but fragments of the inactive virus pose no increased risk to human health.
Additional research released April 26, studying 297 samples of dairy products found in retail stores in 38 states, again confirmed milk safety, with no detection of live, infectious virus, due to pasteurization.
On May 1, FDA shared a further set of results from a national commercial milk sampling study underway in coordination with USDA. The study included 297 total retail dairy samples. New preliminary results of egg inoculation tests on a second set of 201 quantitative polymerase chain reaction (qPCR)-positive retail dairy samples, including cottage cheese and sour cream, in addition to fluid milk, show that pasteurization is effective in inactivating HPAI (H5N1). This additional preliminary testing did not detect any live, infectious virus.
Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted or destroyed so that it does not enter the human food supply. In addition, pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk. Pasteurization is required for any milk entering
FDA’s longstanding position is that unpasteurized, raw milk can harbor dangerous microorganisms that can pose serious health risks to consumers, and FDA is reminding consumers of the risks associated with raw milk consumption in light of the HPAI detections.
Specifically regarding raw milk cheese, the FDA has said, "Because of the limited information available about the transmission of HPAI (H5N1) in raw milk, the FDA recommends that industry does not manufacture or sell raw milk or raw milk cheese products made with milk from cows showing symptoms of illness, including those infected with avian influenza or exposed to those infected with avian influenza."
ADDITIONAL RESOURCES
USDA-APHIS Detection of Highly Pathogenic Avian Influenza in Dairy Herds: Frequently Asked Questions