Bird flu outbreak 2025: Symptoms, prevention, Michigan backyard chicken infection concerns

Whether you already have a backyard chicken coop or are considering investing in some chickens, news about bird flu might have you worried about the potential health risks.

Here's what you need to know about the highly pathogenic H5N1 avian influenza, and what bird flu might mean to you, your chickens and pets.

What is bird flu?

Bird flu is an influenza A virus that causes respiratory disease in birds and can spread to other animals and humans, too. There are several subtypes of bird flu viruses, and the severity of illness they cause can vary, depending on the strain of bird flu and the type of animal that's infected.

Some of types of bird flu, like the highly pathogenic H5N1 avian influenza virus that's been circulating in the U.S. since 2022, are extremely infectious among many types of birds, including turkeys, chickens and geese.

The H5N1 virus has a fatality rate of 90% or higher among poultry, according to the U.S. Centers for Disease Control and Prevention, but it can trigger a puzzling array of symptoms in other animals.

In cows, the H5N1 avian influenza virus seems to infiltrate the mammary system. High levels of the virus have been detected in their milk, slowing production and sometimes causing thick, clotted milk. Cows get fevers, and don't eat and drink like they should. Sometimes pregnant cows miscarry.

Barn cats that drank raw milk from sick cows also were infected with bird flu and developed neurological symptoms, eye and nose discharge; many died. Fox kits also have been reported to have neurologic symptoms when they get H5N1 infections, including tremors, blindness and lethargy, before they die.

What are the symptoms of bird flu in humans?

Symptoms vary, depending on the type of bird flu virus that caused the infection.

The H5N1 bird flu now circulating in the U.S. has caused mostly mild symptoms in the 67 people who've had known infections since 2022. Those symptoms include conjunctivitis, also known as pink eye, along with nasal congestion and cough.

However, two recent cases show that the H5N1 virus now circulating in the U.S. and Canada also can cause severe pneumonia and death in people.

A 13-year-old girl in British Columbia was infected in November with H5N1 bird flu. A report about her case was published in the New England Journal of Medicine, detailing mutations in the virus that allowed it to replicate in the girl's respiratory tract. She was so sick, she was hospitalized for two months and needed extracorporeal membrane oxygenation, also known as ECMO, which acts as an artificial heart and lungs when a person is so critically ill their own heart and lungs cannot function.

The H5N1 bird flu virus also killed a person in early January who'd been hospitalized in Louisiana. The Louisiana Department of Health reported that the person was exposed to both a backyard flock and wild birds, was older than 65 and had underlying medical conditions.

In other parts of the world, roughly half of the people infected with different subtypes of the H5N1 bird flu virus died from it, according to the World Health Organization. Many scientists and public health experts are concerned that the H5N1 bird flu virus circulating now in the U.S. could mutate in a way that makes it more transmissible and more deadly in people.

What are the symptoms of bird flu in chickens?

Chickens and other poultry may not have any symptoms at all before they die suddenly of the highly pathogenic H5N1 bird flu virus, the American Veterinary Medical Association reports.

Others may have low energy or appetite; nasal discharge; coughing; sneezing; reduced egg production; purple discoloration or swelling of the wattles, comb, and legs; lack of coordination; torticollis, or twisting of the head and neck, and diarrhea, according to the U.S. Department of Agriculture.

Can bird flu in chickens be treated?

There is no treatment for highly pathogenic bird flu in chickens and other poultry, the AVMA said. The USDA says the only way to slow the spread of the disease is to depopulate all affected and exposed poultry.

"It is extremely rare for poultry to recover from HPAI," the American Veterinary Medical Association wrote on its website. "For other birds, the chance of recovery depends on the severity of their infection and their species, as some bird species are more resilient to HPAI than others."

What should I do if I suspect bird flu in my flock?

Report it right away. Call MDARD at 800-292-3939 during normal business hours or 517-373-0440 after business hours and on weekends.

If you suspect bird flu in wild birds or other wild animals, report it by calling the state Department of Natural Resources Wildlife Disease Laboratory at 517-336-5030 or by filling out the Eyes in the Field online form: https://www2.dnr.state.mi.us/ors/Survey/4

You also should:

• Wear personal protective equipment such as N95 face masks, vented safety goggles, gloves, boots and/or boot covers, coveralls and hair covers if you go within about 6 feet of sick or dead animals, their animal feces, litter, and any other material that could be contaminated by bird flu, the CDC says.
• Isolate the sick and/or dead birds from other animals and people to prevent exposure.
• Work with state and local health officials to monitor your health and the health of others who might have been exposed to the virus. Watch for new respiratory symptoms as well as eye infection or redness for 10 days after the last exposure to the sick animals. If symptoms develop, get tested right away for influenza A and tell your medical provider that you were exposed to animals with bird flu.
• Use biocontainment and disinfection practices to ensure no people or animals go into the potientially contaminated area. The USDA offers biosecurity tips and best practices here: https://www.aphis.usda.gov/sites/default/files/fsc-birds-checklist-english.pdf

Are my pets safe from bird flu?

It depends on the pet. Of course, birds are very much at risk from the virus and can contract it through exposure to other infected birds — wild or domestic — or their feces, mucus or saliva or contact with surfaces contaminated with their feces, mucus or saliva.

Cats also are extremely susceptible to the H5N1 bird flu and are at risk of developing neurological symptoms and dying if they're infected with H5N1 bird flu.

They can get the virus by drinking raw, unpasturized milk, eating raw poultry and through exposure to sick or dead wild birds, domestic poultry and backyard flocks.

In December, Portland, Oregon-based pet food manufacturer Northwest Naturals recalled a batch of its pet food containing raw turkey after an indoor house cat in Oregon died and the food later tested positive for H5N1 bird flu, according to the AVMA.

The 2-pound Feline Turkey Recipe raw frozen food had use by dates of May 21, 2026, and June 23, 2026, and was distributed in Michigan as well as Arizona, California, Colorado, Florida, Georgia, Illinois, Maryland, Minnesota, Pennsylvania, Rhode Island, Washington and British Columbia, Canada.

There also is evidence ferrets get extremely sick from H5N1 bird flu, and can die from the virus.

While dogs can get infected by the H5N1 bird flu, reports of illness among dogs are rare. When they get sick, the symptoms have been mild, the CDC reported.

Veterinarians urge pet owners to ensure their cats and dogs don't hunt birds or scavenge the carcasses of birds or other animals. They also should avoid contact with other infected animals, such as cows and poultry and unpasteurized milk.

Contact Kristen Shamus: kshamus@freepress.com. Subscribe to the Detroit Free Press.