Concerns about bird flu are growing among health officials weeks after the first person in the United States died from the virus, and as cases of bird flu grow among animals and humans.
Minnesota health officials are traveling across the state to provide preventative measures and vaccinate farm workers and their families against influenza in an effort to curb the spread. Minnesota has no cases of bird flu infection in humans, but does have active infections among poultry and dairy cows.
A 65-year-old man in Louisiana was hospitalized last month after contracting the virus, marking the first severe case in humans in the United States. The Louisiana Department of Health reported earlier this month that the man, who was exposed via wild birds and a personal flock of backyard poultry, had died, marking the first recorded human death from the virus in the country.
Here are answers to some frequently asked questions about bird flu:
What is bird flu?
The H5N1 virus, known commonly as avian flu or bird flu, is a virus that is carried by migratory and aquatic birds like ducks and geese. Bird flu has been circulating since the 1990s after first being detected in Southeast Asia
Bird flu spreads when birds like poultry come in contact with wild birds carrying the virus, typically by interacting in bodies of water like a pond, or near them. Wild birds shed the virus in their saliva, mucus and droppings, which can get on farm equipment and infect domesticated chickens or turkeys, as well as other farm animals, including mammals.
Dr. Stacy Holzbauer, state public health veterinarian with the Minnesota Department of Health, said the first case of poultry in the United States contracting this strain of the H5N1 virus was reported early last year. The virus has since infected several other species of animals, including domestic cats and aquatic mammals.
Since 2022, more than 200 mammal species have contracted the virus, according to the U.S. Centers for Disease Control and Prevention (CDC).
The first reported case of bird flu spreading to dairy cows in the country was reported in late March 2024. More than 900 herds in at least 16 states, including Minnesota, were infected. Scientists have found that infected cows shed the virus in their milk, leading to bird flu infections in humans and other animals, such as cats, that consumed raw, infected milk.
The virus can spread through contaminated farm equipment like milking machines, bedding and feces, making dairy cows – in addition to domesticated poultry – vulnerable to infection.
A concern, Holzbauer said, is that if an individual contracts seasonal influenza and bird flu at the same time, the two viruses could mingle and mutate, creating a new, more contagious and resistant strain of flu.
“The virus is always changing,” she said. “The virus is very promiscuous, and it’s swapping genes all the time.
“If someone is infected with a seasonal influenza virus, the routine virus that we see every winter, and is also infected with an H5N1 virus, then those two viruses kind of swap genes, and then it creates this new virus that could be more easily transmitted from person to person.”
How does bird flu spread between humans, or humans and other mammals?
Most humans and other mammals, like cats, who contract the virus are infected by consuming raw milk or infected poultry, or by coming into contact with the saliva, mucus or feces of already-infected domesticated animals like chickens, turkeys and dairy cows.
Human-to-human spread, as well as general mammal-to-mammal spread, has not yet been reported. However, scientists and health officials recognize that it is possible.
What is the current risk to humans?
The people at highest risk for contracting bird flu are farm workers who come in close contact with chickens, turkey or cattle, as well as workers at poultry processing plants involved in culling birds.
While mammal-to-mammal transmission of bird flu has become increasingly more likely, the general public’s risk of contracting bird flu remains low, said Jeff Bender, a professor in the University of Minnesota’s School of Public Health.
“If you’re basically somebody that has a backyard flock and your chickens die, and you are cleaning up after them, you might be at risk,” he said. “Or if you’re working on a dairy that has evidence of avian influenza, then you potentially could be at risk, and so there’s extra precautions that are necessary.
“But for the general public, they’re at a pretty low risk for H5N1 or this particular strain that we’re seeing right now.”
Since the virus was first detected in the 1990s, Holzbauer said, there have been sporadic human infections associated with people like farmers who have direct contact with infected animals.
A total of 67 people have been infected with bird flu in the United States since 2022, with 66 of them occurring in 2024, according to the CDC. Of those 67 infections, about 40 were among dairy farm workers who milk cows.
The most common symptom exhibited in humans with bird flu is conjunctivitis, or pink eye, although many have also displayed mild flu-like symptoms like sore throat, fever, runny nose and a cough, among others.
Is there a vaccine for bird flu?
There is currently no vaccine for bird flu, but last week, the U.S. Department of Health and Human Services announced $590 million in funding for Moderna to expedite the development of an mRNA vaccine that would target the H5N1 strain that is currently circulating.
The funding is on top of $176 million the federal agency gave to the pharmaceutical company, which developed a vaccine for COVID-19, last July for the same purpose.
How can you protect yourself?
Bender suggested that farmers, their families and others who come in contact with animals take precautionary measures such as limiting contact between wild birds known to carry the virus and domesticated birds. For people with backyard chickens, that could mean adding extra netting around enclosures and avoiding bodies of water like ponds and streams, where ducks and chickens can mingle.
For larger farms, he recommends constant communication with local animal health officials or veterinarians, providing protective equipment and clothing for workers, and limiting contact with sick birds or cows.
“The good news is that generally, the illness that we’re seeing in people is mild,” Bender said. “But I think it’s really important that we really kind of continue to monitor, to have rapid diagnostic tests and abilities for people who are working in those environments to get tests and then be able to get treatment if need be.”
Bender also recommends washing hands with soap for at least 20 seconds and getting the seasonal flu shot.
Should I continue to feed wild birds or set out a bird bath?
Although bird baths and feeders typically cater to songbirds and the risk of infection remains low for humans, they may attract wild birds that can carry the virus.
The CDC recommends avoiding contact with wild birds like ducks and geese, and to observe them from a distance. The agency also recommends avoiding touching any surface that could be contaminated with the saliva, mucus or feces of wild birds.
How are state officials addressing the flu?
Rosa Perez, an infectious disease farmworker liaison with the Minnesota Department of Health, and her team have been travelling the state in recent months to share information about the virus and to administer free flu shots for farm workers and their families.
“We bring out a team to vaccinate family members, from children to grandparents, extended family … usually they include everybody in the family,” Perez said. “We’re just getting out the word and being there to facilitate the community’s needs, and providing accessibility to vaccines and information.”
The team has held eight influenza vaccination clinics since early October, providing flu shots for more than 250 farm employees and their families. They plan to continue their efforts into the remainder of the flu season, including popup clinics in Mower, Blue Earth and Wabasha counties later this month.
Upcoming clinics:
- 1/25/25: Mower County – Austin Community Ed. Preschool Resource fair
- 1/30/25: Blue Earth County – Shared Spaces, Copal
- 1/31/25: Wabasha County – LPH collab with dental services
- 2/15/25: Benton County – Hacer collab, location TBA
- 2/17/25 : Carver County – Carver County Dairy & Beef Expo
- 2/27/25: Blue Earth County – Shared Spaces, Copal
- 3/27/25: Blue Earth County – Shared Spaces, Copal
What does bird flu look like outside of the United States?
As of mid-December, this current outbreak of the H5N1 virus has reached 108 countries across five continents, according to United Nations health officers.
More than 300 million birds worldwide have succumbed to the virus, which continues to infect and kill more mammals, including endangered species like polar bears and tigers.
The majority of human infections have been reported in the United States, but cases have also been reported in Australia, Canada, China, Cambodia and Vietnam. Although the United States reported its first death due to bird flu this month, more than 400 people around the world have died from the virus since 2003, according to the World Health Organization.
