Highly Pathogenic Avian Influenza

This web page provides key EPA resources and other links of interest on the outbreak of the Highly Pathogenic Avian Influenza A (H5N1) in poultry and livestock. In response to the outbreak, U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has increased efforts to protect U.S. poultry and livestock, expanded wild bird surveillance for Avian Influenza, and taken several recent actions to address illness among dairy cows.

As of October 22, 2024, APHIS has confirmed cases of highly pathogenic avian influenza (HPAI) in domestic livestock in 14 states. For up-to-date information, visit Highly Pathogenic Avian Influenza (HPAI) Detections in Livestock.

As of the beginning of 2024, APHIS has confirmed cases of HPAI in over 1,100 flocks, both commercial and backyard, in nearly all 50 states. For more information on affected flocks, visit the Confirmations of Highly Pathogenic Avian Influenza in Commercial and Backyard Flocks page. USDA has observed little to no mortality and reports that cattle may recover with supported care. For more information on affected wild bird populations, visit the Detections of Highly Pathogenic Avian Influenza in Wild Birds page.

Centers for Disease Control and Prevention (CDC) sees the current public health risk as low. On April 24, 2024, USDA issued a press release stating APHIS microbiologists identified a shift in an H5N1 sample from a cow in Kansas that could indicate that the virus has an adaptation to mammals. CDC conducted further analysis and concluded that the substitution has been seen previously in other mammalian infections and does not impact viral transmission. For current information on the public health risk of HPAI, visit the CDC’s Avian Influenza Current Situation Summary.

HPAI is a serious disease and requires rapid response because it is highly contagious and often fatal to chickens and other birds. Since February 2022, HPAI H5N1 has been confirmed by USDA APHIS in wild birds, commercial operations, and backyard flocks throughout the U.S.

The USDA’s APHIS is the lead federal agency for responding to a large-scale animal disease outbreak. EPA provides guidance on carcass disposal and is responsible for registering pesticide products, including disinfectants for use against Avian Influenza A. Additionally, EPA provides guidance on biosecurity measures to prevent spread of the disease to other facilities.

What is Avian Influenza?

Avian influenza, often called “Bird Flu,” refers to illnesses caused by a number of different flu viruses. There are two main forms of the virus:

• Low pathogenicity (LPAI)
• Highly pathogenic (HPAI)

LPAI is fairly mild in birds, while HPAI (also called Avian Influenza A) is a much more serious threat to bird health and potentially livestock. Avian influenza viruses do not usually infect humans, although rare cases of human infection with these viruses have been reported.

There are various strains of “bird flu” with names such as H5N1 or H7. While each strain has unique properties, the strains have many similarities, particularly when it comes to potential environmental impacts. Such environmental risks may include, but are not limited to, the following:

• Poor carcass management when birds die from AI or are euthanized to prevent the spread of the disease.
• Improper management of wastewater from cleaning and disinfecting practices.
• Improper disposal of the personal protective equipment that responders wear  to comply with Occupational Safety and Health Standards 29 CFR 1910 Subpart I.

EPA Resources on Avian Influenza

• EPA’s Registered Antimicrobial Products Effective Against Avian Influenza [List M] https://www.epa.gov/pesticide-registration/epas-registered-antimicrobial-products-effective-against-avian-influenza
• Biosecurity Guidance for Visits to Livestock and Poultry Facilities  https://www.epa.gov/compliance/guidance-biosecurity-procedures-visits-livestock-and-poultry-facilities
• Carcass Disposal https://www.epa.gov/homeland-security-waste/carcass-management-during-avian-influenza-outbreak

USDA Animal and Plant Health Inspection Service Guidance for Avian Influenza

For current USDA orders and recommendations to protect livestock health, updates to where livestock have been detected with HPAI, and additional descriptions of how this outbreak may affect livestock, visit Highly Pathogenic Avian Influenza (HPAI) Detections in Livestock.

APHIS monitors large numbers of wild birds, commercial flocks, and backyard birds in North American through its ongoing bird surveillance programs. With the recent detections of the Eurasian H5 strain of HPAI in wild birds and domestic poultry in the United States, APHIS requests that bird owners review their biosecurity practices and stay vigilant to protect poultry and pet birds from this disease.

• For information on recent, detected HPAI infections, visit the USDA APHIS page Detections of Highly Pathogenic Avian Influenza.
• For information on how this outbreak may affect poultry farmers and how to prepare flocks, visit USDA APHIS Defend the Flock.

CDC Guidance for Avian Flu Outbreaks

The Centers for Disease Control and Prevention (CDC) tracks incidents of avian influenza worldwide and provides information on the rare situations where humans have contracted the disease from close contact with contaminated birds, contaminated surfaces, or via air droplets.

For the most current information on the H5N1 avian influenza, visit the CDC web page Avian Influenza Current Situation Summary.