What is avian flu?
Avian flu, also known as avian influenza, is a highly contagious viral disease that can infect birds such as chickens, turkeys, ducks, geese, and wild birds. There are many different strains of avian influenza viruses that vary in how severe they are. Some strains cause only minor symptoms in birds while others are highly pathogenic, meaning they cause severe illness and death in domestic poultry.
The most common strains of highly pathogenic avian flu that have caused outbreaks in poultry around the world are H5N1 and H7N9. When domestic birds become infected with these strains, it can lead to overwhelming sickness and flock deaths. Highly pathogenic strains like these are concerning because they have led to human infections and deaths in some parts of the world.
How do wild birds spread avian flu?
Wild aquatic birds like ducks and geese are considered natural reservoirs for avian influenza viruses. This means the viruses have adapted to live and multiply inside these bird species without making them very sick. Many wild birds can be infected with avian flu viruses without showing symptoms of being sick.
Since wild birds migrate and fly over large areas, they are able to spread avian flu viruses great distances through their feces, mucus, and saliva. The virus gets transmitted from one wild flock to another as birds congregate and interact at wetlands, ponds, and other water sources.
Domestic poultry like chickens are not natural hosts of avian flu viruses. When a wild bird introduces a virus to a poultry flock, it can quickly spread and turn deadly for the flock if it is a highly pathogenic strain. Backyard chicken flocks and commercial poultry operations are both at risk.
Should I stop feeding wild birds?
One question backyard bird enthusiasts and nature lovers have is whether they should curtail backyard bird feeding and bird baths to help reduce avian flu spread. Some key considerations include:
- There is limited scientific evidence that stopping backyard feeding will significantly reduce spread to domestic flocks. Migratory waterfowl that can harbor flu viruses don’t typically frequent backyard feeders and bird baths.
- Backyard birds often rely on supplemental feeding, especially in winter months when natural food is limited. Completely stopping feeding may negatively impact the birds.
- Consider removing bird baths and feeders only if avian flu is detected in wild birds in your local area.
- Clean feeders and baths regularly with a 10% bleach solution to help disinfect.
- Avoid handling sick or dead birds. Report any dead bird sightings to wildlife officials for tracking purposes.
How can I protect my flock from avian flu?
Here are some key steps backyard chicken keepers can take to try to reduce avian influenza risks:
- Prevent contact between poultry/pet birds and wild birds by keeping birds enclosed in an outdoor run or coop.
- Use bird netting over outdoor enclosures to stop wild birds from flying in.
- Wash hands and scrub boots before and after entering the coop to remove germs.
- Isolate any birds returning from poultry shows for 30 days before reintroducing to the flock.
- Avoid introducing new birds from unknown or uncertified disease-free sources.
- Report signs of illness or unexpected deaths in your flock to your avian veterinarian.
What are the symptoms of avian flu in birds?
Possible symptoms of avian influenza include:
- Sudden death without clinical signs
- Lack of energy and appetite
- Decreased egg production
- Soft-shelled or misshapen eggs
- Swelling around the eyes
- Purple discoloration of the wattle, comb, and legs
- Coughing, sneezing, runny nose
- Incoordination, stumbling
- Diarrhea
However, it is important to note wild birds can carry and spread the virus without appearing sick. Monitoring for unexplained sickness and deaths within a flock is important. When avian flu strikes a flock, death loss can be rapid and affect most birds within 48 hours.
Can I get sick from avian flu?
According to the CDC, the risk to the general public’s health from current avian flu viruses is low. There have been some past infections in humans from being in close contact with sick birds or contaminated environments. Symptoms in humans range from:
- Conjunctivitis
- Influenza-like illness (fever, cough, sore throat, muscle aches)
- Pneumonia
- Acute respiratory distress
The virus does not currently spread easily from birds to people or spread easily between people. But health officials monitor avian flu viruses closely for any signs the virus is mutating or acquiring the ability to infect humans more readily.
Is it safe to eat poultry products?
Properly cooking poultry products to an internal temperature of 165°F kills any viruses present, including the avian flu virus. So it is considered safe to eat properly cooked chicken, turkey, and eggs, even during a bird flu outbreak affecting domestic flocks.
There is no evidence people can get flu viruses from eating fully cooked eggs or poultry, even in areas with outbreaks in poultry flocks. Still, backyard flock owners should avoid consuming eggs or meat from sick birds. As extra precaution, use a food thermometer to check the internal temperature of cooked poultry reaches 165°F.
Conclusion
Avian influenza is a concern for both the poultry industry and backyard bird keepers. Wild aquatic birds can harbor and transmit bird flu viruses through migration. Backyard flock owners should be vigilant about biosecurity measures to protect their birds from introducing a virus from the wild through feed, water, enclosures, and new bird introductions. Avoiding contact with wild birds, isolating new birds, and monitoring for symptoms are key protective steps.
The general public health risk from avian flu remains low when proper cooking temperatures are used. While there is limited evidence stopping backyard bird feeding will significantly influence spread, it can be a reasonable temporary precaution in areas with infected wild birds. Since much is still unknown about avian flu transmission dynamics, backyard bird enthusiasts should follow the advice of agricultural and wildlife experts in their region to balance the benefits of birdfeeding with sensible biosecurity steps for backyard flocks.
Frequently Asked Questions
How long can avian flu survive in the environment?
Avian influenza viruses can survive for extended periods in water and wet feces. One study found the virus survived:
- Over 200 days in water at 50°F
- Over 100 days in wet manure pile at 39°F
- Up to 30 days at 72°F in water
- Between 7-16 days on various hard surfaces at 72°F
High ambient temperatures and UV radiation from sunlight can shorten how long the virus survives. Proper disinfection is needed to inactivate viruses that have contaminated surfaces or equipment.
Which bird species are most at risk of infection?
Domestic poultry like chickens, turkeys, and ducks are most vulnerable to rapid spread and severe illness from avian flu infection. Birds that live near water sources and migratory flyways are more likely to encounter infected wild birds.
Wild waterfowl like ducks and geese along with shorebirds are natural reservoirs for low-pathogenic flu strains. Raptors like hawks and eagles are rarely infected but can potentially transport the virus mechanically on feathers or feet.
What types of disinfectants kill the avian flu virus?
Avian flu viruses are susceptible to a number of common disinfectants. However, disinfectants must be used properly at correct dilutions and contact time.
Recommended agents include:
- 10% bleach solutions with a 10 minute contact time
- 70% ethanol solutions
- Common farm disinfectants like 1 Stroke Environ, Tek-Trol, One Stroke Environ
- Detergents and soaps
Rinsing off surfaces before applying disinfectant and wearing proper protective gear is important. Never mix bleach with ammonia, acids, or other chemicals which can cause hazardous gas formation.
Is there an approved vaccine for avian flu in domestic birds?
There currently is not an approved vaccine for H5 or H7 avian influenza viruses in the United States. Vaccines are sometimes used overseas in high risk situations to aid in control efforts.
Routine vaccination is generally not recommended due to several reasons:
- Concerns vaccines could mask spread of field virus
- Challenge of keeping vaccine strains up to date with actively mutating field viruses
- Costs of stockpiling and delivering adequate doses
- Trade implications due to serologic testing issues in vaccinated flocks
Instead, tight biosecurity and surveillance are the primary control strategies. Spatial or temporal emergency vaccination programs are considered in severe outbreaks when depopulation capacity is overwhelmed.
Key Facts and Data
Reported 2022-2023 Wild Bird Avian Flu Detections
Species | Positive Birds |
Snow geese | 9 |
Canada geese | 58 |
Ducks | 396 |
Swans | 42 |
Hawks | 14 |
Eagles | 7 |
Total wild birds | Over 5000 |
2022-2023 H5N1 Outbreak Impact
Metric | United States | Worldwide |
Flocks affected | 278 | Over 5000 |
Birds culled | 58 million | Over 175 million |
Countries affected | 1 | Over 70 |
CDC Estimated Human Infections from Avian Flu Viruses
Virus Strain | Infections |
H5N1 | 858 |
H7N9 | 1568 |
H9N2 | 4 |
H5N6 | 21 |
Total | 2451 |