Avian Flu Widespread on Cape Cod – What to know

07 February, 2025 – CAPE COD, MA – The increase avian flu cases represents the biggest the U.S. has seen to date. Although Massachusetts has no known human cases, state and local authorities say following public guidelines will mitigate spillover and limit the risk of mutations.

What Is The Avian Flu?

The Highly Pathogenic Avian Influenza, HPAI or the avian flu, is a highly transmittable virus naturally carried by migratory birds, primarily water fowl. The new strain, H5N1, entered the U.S. in late 2021 and in 2022 the first infected wild birds in Massachusetts were detected on Cape Cod. It has spilled over onto domestic birds and dairy cattle, from which humans have caught the disease. There have been no known human in Massachuetts to date. Dairy cattle have been routinely tested in Massachusetts once a month since August last year. One poultry farm with 30 birds in Plymouth – the only one in the state –had to be euthanized in late January 2025.

How many people have been infected in the U.S?

In the U.S. a total of 67 people have been infected since 2024, 24 through domestic birds, 40 through cattle. For three people the source could not be traced. “We have not seen human to human transmission. and if you have not handled or been around the direct environment of sick or dead birds, your risk for being infected with avian influenza is still very low at this time,” says Lea Hammer, Contract Epidemiologist for Barnstable Health Department.

What are the symptoms?

For most people the symptoms are very mild, resembling a flu or a cold, sometimes with red and swollen eyes. In January 2025 one person died. “Folks with underlying medical conditions that have a hard time fighting off respiratory infections could consider themselves to potentially be a higher risk group,” Hamner says. She adds that people on immunosuppressive therapies vulnerable to infections could also have a harder time with the avian flu. The number of people infected to date is to small to assess risk groups, Hamner says, and draws her conclusions of seasonal flu patterns.

Authorities stress to stay away from dead or sick birds, but to report any sightings of groups of five dead birds or any number of dead or sick raptors. John Herbert, director of bird conservation at Mass Audubon, says you do not have to be a birder to be able to spot the illness. “The avian flu affects their cognitive ability. So you can often see if they're struggling to fly, if their head is moving in odd directions, or if they’re not acting right, they can’t fly right, they’re not walking right,” Herbert says. “That’s when we ask our members and the public to report those sightings to the state of Massachusetts.”

Why is there an outbreak now?

The new strain is called H5N1 and entered the U.S. in late 2021 via wild birds. In 2022 the first infected wild birds in Massachusetts were detected on Cape Cod. John Herbert says he usually sees an uptick in avian flu cases during the winter months when birds normally congregate closer together, but MassWildlife believes that because this winter has been colder than recent years it is causing the birds to flock even closer in less and smaller areas of open water, leading to the unprecedented wide spreading we are seeing now, both in number of infected birds as well as geographically.

It is difficult to know how many wild birds have been infected, but state authorities estimate between 500-1000 birds with suspected – not preliminary positive – avian flu have been reported this season.

Are Backyard Flocks Safe?

According to Massachusetts Department of Agricultural Resources 138 million domestic birds have been impacted since 2022, leading to a rise in egg prices. Any flocks of under 3,000 birds count as non-commercial, there are several hundred backyard flocks in Massachusetts. According to MDAR, the state’s policy is to cover the costs of depopulations of commercial flocks.

All domestic poultry flocks on Cape Cod are backyard flocks. Owners are urged to keep their animals in an enclosure to limit contact with wild birds, and report any signs of illness to MDAR. What about consuming meat, eggs and dairy? According to the Center For Disease Control and Prevention cooking beef, poultry and eggs all the way through kills the virus. For eggs and poultry meat that means an inner temperature of 165°F, for ground beef 160°F and whole cuts of beef should reach 145°F then rest for 3 minutes. Pasteurized milk is safe.

Pets, especially cats, tend to become seriously ill, according to state authorities, keep cats indoors and dogs on leash. Do not feed your pets raw poultry or raw pet food.

Can the virus mutate?

The more people that are affected the higher the risk of the virus getting used to humans and mutating. The risk of the virus spreading among the general public is low. If a person who has not been in contact with sick or dead birds has flu-like symptoms, it is unlikely the avian flu. However, if somebody has been handling birds and is showing symptoms it is important to let your health care provider know, so they can order test kits specifically designed for the avian flu. “The thing about flu is it’s pretty crafty. It can move and adapt and shift,” says Lea Hamner. “Reducing the opportunity for it to do that is pretty critical. And so reducing the number of human infections for it to mutate within a human to become more adaptable to humans is important.”

How Can I Help Sick Raptors

Bald eagles have died in the state and the U.S. due to the virus, MassWildlife says raptors are especially exposed to the virus since they feed on carcasses. They believe robust populations will be able to deal with the virus and remain stable, but Mass Audubon says reports from the public help them monitoring and plan ahead for vulnerable bird populations.