Avian influenza, commonly known as bird flu, has been spreading in northern Illinois, particularly in areas like Woodstock that are along major migratory routes. This map from the CDC shows where the virus was detected in wastewater as of January 2, 2025.
The virus can kill chicken flocks, both commercial and backyard, so it’s important for chicken keepers in this area to be aware and take precautions.
How Bird Flu Spreads
There are several different strains of the bird flu virus, including the H5N1 variety, which can transfer to humans. The virus spreads when chickens come into contact with infected birds. Chickens and other fowl can also contract the virus through indirect contact including shared water and soil or other surfaces contaminated with droppings. Wild waterfowl, like ducks and geese, can carry the virus without showing symptoms and are a major source of infection for domesticated birds. They may release droppings when flying, which contaminate areas where chickens forage.
Risks to Humans and Chickens
The Illinois Department of Public Health (IDPH) warns that the H5N1 strain of bird flu can infect humans through contact with infected birds or contaminated surfaces. Human symptoms include fever, cough, severe respiratory distress, and conjunctivitis, among others. These symptoms may resemble other respiratory illnesses and require careful clinical evaluation for accurate diagnosis. Early detection and treatment are critical.
Poultry specialist Dr. Anne Staudenmaier states that the symptoms of the virus in chickens can vary, depending on the strain. Some symptoms may be caused by other conditions, but there is always concern when multiple birds in a flock show signs in a short period of time, as opposed to just one bird, or over a period of weeks or months. These signs include:
- Decreased egg production or abnormal eggs
- Swelling of the head/comb/wattles/eyelids
- Purple discoloration of the wattles/comb/legs
- Nasal discharge, coughing, sneezing
- Diarrhea
- Lack of coordination
- Decreased appetite
- Sudden death
For chickens, bird flu is highly lethal, with survivors often carrying and spreading the virus, including to other flocks. These outbreaks can cause significant economic losses and disrupt poultry operations, emphasizing the need for stringent biosecurity measures.
While not all strains of avian flu are deadly, the virus is similar to the human flu virus: it mutates and changes over time, meaning there is always a chance a virulent strain that could affect humans may develop. In fact, recent reports show bats carrying several new avian influenza strains. For this reason, it is critical to manage avian influenza effectively. For more details, refer to the Illinois Department of Public Health’s advisory.
Protecting Your Backyard Flock
Wild birds are responsible for most cases of transmission to backyard flocks. Shore birds and waterfowl are considered to be natural hosts for influenza viruses and often spread disease during migration. Illinois is on a major migration path, called the Mississippi River flyway, which puts resident flocks at higher risk. To protect your flock, Dr. Geoff Lossie, formerly of Purdue University, points to the importance of biosecurity, especially now:
- Limit the amount of contact that wild birds have with your birds, including access to food and housing.
- Avoid hunting waterfowl because hunters can bring the virus back to their flocks.
- Limit all unnecessary visitors, especially those who have their own poultry.
- Do not interact with other keepers’ birds.
- Do not share poultry equipment (feed/water dishes, cages, incubators, etc.) with other keepers.
- Keep birds in an enclosed area with a roof to prevent contact with droppings from infected waterfowl flying overhead.
Dr. Lossie suggests reading the information here.
What to Do if Your Flock is Infected
According to the USDA, if birds exhibit show symptoms of avian flu or might have been exposed to birds with the disease, producers or bird owners should immediately notify federal or state animal health officials. All bird owners, whether commercial producers or backyard enthusiasts, should continue to practice good biosecurity, prevent contact between their birds and wild birds, and report sick birds or unusual bird deaths to state/federal officials, either through their state veterinarian or through USDA’s toll-free number at 1-866-536-7593. Additional information on biosecurity for backyard flocks can be found at Healthy Birds.
Local Recommendations
Health officials in DuPage County urge residents to follow these recommendations, as outlined by the DuPage Forest Preserve District:
- Avoid feeding wild waterfowl. This will invite the birds to flock in a specific area, which can allow the virus to spread. It also increases risk of human contact.
- Feeders for songbirds are generally low risk. Do clean and disinfect the feeders when refilling.
- If you see more than five sick or dead birds in an area, report it immediately to the Illinois Department of Natural Resources (IDNR) wildlife biologist for DuPage County.
- Safely dispose to dead birds, following the guidelines on the DuPage County Health Department avian flu webpage.
- Keep pet birds and other fowl inside until risk decreases, or keep them in an enclosure with a roof that wild birds cannot enter.
- Wildlife rehabbers may be limited in their operations due to tighter restrictions, so be understanding if they are unable to admit certains species.
For More Information
- Bird flu confirmed in waterfowl in Woodstock, ‘numerous locations’ in Illinois
- Advice from a Vet: How to Protect Your Flock from Avian Influenza
- Avian Influenza (H5 Bird Flu)
- Health Alert: Novel Influenza A(H5N1) Virus
By staying informed and proactive, you can help safeguard your flock and reduce the spread of avian influenza.
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