
H5N1
What is the Bird Flu?
H5 bird flu refers to various strains of influenza A viruses that typically infect birds. These viruses mainly affect wild birds, but can also infect other animals, both wild and domestic (e.g., cats, cows, dogs, foxes). The severity of the infection varies depending on the strain and species.
Highly pathogenic avian influenza (HPAI) strains are deadly to domestic poultry and can wipe out entire flocks within days, making it a significant threat to poultry, animal health, and consumerism.
Low pathogenicity avian influenza (LPAI) strains typically cause few or no signs of illness. These strains occur naturally in wild birds worldwide. However, some LPAI strains can become highly pathogenic in poultry, posing a concern.
There is a seasonal prevalence of both highly pathogenic and low pathogenic avian influenza, which is influenced by bird migration patterns.
Why are we concerned about H5N1?
H5N1 is a type of avian influenza that has been spreading not only in birds but also in wild and domesticated mammals, as well as through animal products. To the CDC’s knowledge, this is the first time these viruses have been found to spread from poultry to cows and cats through the consumption of untreated products.
The highest-risk groups of animals are poultry flocks (commercial) and dairy cows, along with the farm workers and meat processing facilities that handle these products. While the CDC and other governmental agencies regulate commercial flocks and dairies, this article will focus mainly on backyard flocks and prevention in domesticated animals.
What are the signs of Highly Pathogenic Avian Influenza?
- Sudden death without any prior symptoms of illness (usually within 2–3 days) in multiple birds
- Lack of energy and appetite
- A drop in egg production or soft-shelled, misshapen eggs
- Swelling of the eyelids, comb, wattles, and shanks
- Purple discoloration of the wattles, comb, and legs
- Gasping for air (difficulty breathing)
- Nasal discharge, coughing, sneezing
- Twisting of the head and neck (torticollis)
- Stumbling or falling down
- Diarrhea
How to Prevent This in My Backyard Flock
- Keep your flock indoors, covered, and separated from wild birds, especially waterfowl. Prevent pests like rodents from entering flock houses and coops.
- Isolate any new birds for 30 days to observe for signs of illness before introducing them to your flock, especially if they’ve been at a recent show with other birds.
- Purchase birds from reputable sources to ensure they are healthy. Buy only from National Poultry Improvement Plan (NPIP)-participating breeders, hatcheries, or dealers.
- Limit visitors and traffic on your property and in flock areas to prevent cross-contamination.
- Disinfect shoes, clothes, hands, egg trays or flats, and crates with bleach or other disinfectants.
Bleach Dilution: A 1:32 dilution (1/2 cup bleach to 1 gallon of water) is effective against avian influenza. Pine-Sol is another example of a phenolic disinfectant that many people have at home.
- Wash hands and scrub boots before and after entering poultry areas. Wear disposable boot covers and coveralls, or use designated shoes for the flock.
For more information, see USDA/APHIS guidelines on “Prevent Avian Influenza at Your Farm: Improve Your Biosecurity With Simple Wildlife Practices.”
Is there a treatment?
Unfortunately, there is no treatment for avian influenza due to its high rate of spread and mortality in backyard flocks. Once confirmed, the only course of action is depopulation. This measure is essential to prevent the disease from spreading to other flocks and to address public health concerns, as the virus cannot replicate in dead tissues.
Prevention and surveillance are the best strategies to protect your flock.
How to Protect Your Flock
Resources from USDA:
APHIS collaborates with commercial operators, states, and backyard growers to prevent avian influenza and other diseases from spreading in the U.S. poultry population. Protecting the health and safety of poultry is a top priority for all flock owners.
Steps to Take:
- Review biosecurity basics and follow best practices.
- Learn the signs of illness in birds.
- Visit the Defend the Flock Resource Center for information on disease prevention and outbreak preparation.
What about my indoor, indoor-outdoor or outdoor pets that consume animal products?
It’s true that cats and other animals have contracted H5 bird flu and died. The mortality rate is ~70% for cats and 100% for ferrets. To prevent infection:
- Cook meat and animal products to an internal temperature of 165°F to kill the virus.
- Pasteurize milk to kill harmful bacteria and viruses. Even if the virus is present in raw milk, the HTST (High Temperature, Short Time) pasteurization process will inactivate it.
- Avoid feeding raw pet food, treats or animal products to your pets.
- Reconsider outdoor time for cats for the time being
Example: Monarch Raw Pet Food and Public Health confirmed H5 bird flu in four house cats from a household that consumed recalled raw milk. The cats developed severe illness, including neurologic, respiratory, and liver issues, which rapidly progressed to death. (Source: Los Angeles Public Health News Release, December 31, 2024.)
Does Avian Influenza Affect Humans?
Public Health confirmed the first human case of H5 bird flu in Los Angeles County in December 2024. The individual was exposed to infected livestock at a worksite.
According to CDC historical data, avian influenza A viruses rarely infect humans. However, symptoms may resemble those of the common cold or flu, including:
- Eye redness or discharge
- Cough
- Sore throat
- Runny or stuffy nose
- Fatigue, headaches, or muscle aches
- Trouble breathing
- Fever
The overall risk of H5 bird flu to the public remains low, and there is no evidence of person-to-person transmission of the virus.
Can I still feed my outdoor birds if I don’t have chickens?
Most wildlife agencies advise against feeding wildlife in general, as central feeding areas can promote the spread of pathogens. While the most common carriers of H5N1 are waterfowl and gulls, which are not typically backyard visitors, caution is advised.
- Avoid handling dead animals.
- Follow CDC guidelines on reporting dead birds or wildlife.
- If you own poultry, avoid feeding outdoor birds and adhere to strict disinfection protocols.
For further details, see this handout from the New York Department of Health:
Feeding Outdoor Birds