The H5N1 virus — the cause of the current bird flu epidemic — is notorious for its ability to mutate and infect different species. Carried by migratory European fowl to the United States in 2020, an H5N1 mutation triggered a nationwide poultry outbreak in February 2022. The virus soon transformed a second time and jumped species, sickening and killing mammals, including raccoons, squirrels and cats.
In March 2024 the first confirmed cases of bird flu in cattle were documented in Texas and Kansas. According to federal data, 951 cows have now been infected in 16 states (though none in New York). In April, H5N1 mutated again and sickened the first human, a Texas dairy worker. Now bird flu has infected 66 Americans across 10 states, and in January killed a Louisiana senior who was infected by his backyard flock. There have been no human cases in New York.
On Wednesday, Feb. 5, the U.S. Department of Agriculture announced that the virus had mutated once more and reinfected a dairy herd in Nevada. This raises concerns about ongoing risks to cattle and people who tend them; some researchers worry that future viral mutations could cause serious consequences for animal and human health.
Viral strains similar to H5N1 have caused bird flu in the U.S. for more than a century. In the 1920s, the infection killed birds in New York City’s live markets, but did not spread to other species. A viral mutation caused the 1957 “Asian Flu” that killed 1 million people worldwide, including 116,000 Americans.
The current outbreak has ravaged commercial and backyard flocks in all 50 states, resulting in the deaths of 138.7 million chickens, ducks, and turkeys from illness or euthanasia, which is done to prevent spread of the disease. (Eggs must be destroyed, too, which has contributed to the doubling of the average price of a dozen over the past year, to $4.10 in December.) New York State has lost 126,992 birds, including 4,200 in Dutchess County and 250 in Columbia County, according to the United States Department of Agriculture.
The Ulster County Department of Health announced its first case of bird flu – in chickens – on Jan. 29. The infection was confirmed at an undisclosed Hudson Valley farm, and killed all but two of the birds in a flock of 50. (The survivors were euthanized.) The health department also said it would keep the farm owners and the veterinarian who attended the flock under surveillance for 10 days.
The federal Centers for Disease Control and Prevention says that the general public’s chance of catching bird flu remains low. People at risk for infection include those who have unprotected contact with sick birds, cows, or other mammals. The H5N1 virus is spread through animal saliva, mucus and feces: Infected droplets and dust can be inhaled. Bird flu microbes live for long periods of time on contaminated surfaces like farm equipment and feeding dishes; they can be carried on clothing and shoes.
Russell Biezynski of Northwind Farms in Tivoli, urged people not to panic: “We have more than 5,000 turkeys, ducks and chickens. We’ve been in business since 1982 and have always maintained strict hygienic standards. Our flocks have never been sick with anything.” Northwind, which also raises beef, pork, and lamb, sells farm products directly to the public. “Customers must stay in their cars, well away from the birds,” Biezynski said. “We started this rule during Covid-19 and have kept it in place to help keep our flocks healthy.”
Symptoms are generally mild in cattle: 98% of the animals recover and euthanasia is rarely needed. But the virus can be passed from sickened dairy cows to their milk, a potential source of infection to humans. Nearly 99% of American milk is pasteurized, a heating process that kills the H5N1 virus and other harmful bacteria. But 14 million Americans prefer raw milk, a practice the CDC advises against: Contaminated raw milk droplets can linger on surfaces for up to five days and spread disease.
In January 2025, the USDA launched its National Milk Testing Strategy, a monthly screening of Grade-A milk intended for pasteurization; licensed raw milk that won’t be pasteurized is also tested. “We have a raw milk permit,” said Pine Plains dairy farmer Sarah Chase. “The New York Department of Agriculture and Markets (NYSDAM) has always tested our milk every month for contaminants like bacteria. Now it will be screened for bird flu, too.”
Bird flu symptoms are similar to seasonal influenza: fever, cough, sore throat, and sometimes conjunctivitis. Anyone with a virus-like illness who has come into contact with infected animals should call their medical provider. Although there is no evidence that bird flu spreads among people, sufferers should avoid those at higher risk for severe illness, such as the elderly and anyone with chronic medical conditions like diabetes.
The best way to prevent bird flu is to avoid direct exposure to wild birds, poultry or cows that are sick or dead. If you must come into close contact with infected animals, wear recommended personal protective equipment such as goggles, gloves, and a face mask. Wash hands with soap and water frequently. There are no commercially available human vaccines against bird flu, but many experts encourage people at risk to consider boosting their general viral immunity by updating a standard flu shot. Cooking food thoroughly kills the bird flu virus. Poultry should reach an internal temperature of 165 degrees, ground beef 160 degrees; eggs must be firm, not runny.
Federal agencies including the CDC and the Department of Agriculture are monitoring bird flu outbreaks by surveilling wastewater, investigating the possibility of human-to-human transmission, and educating clinicians about the disease. The Department of Health and Human Services recently awarded a $590 million grant to the pharmaceutical company Moderna to accelerate the development of a bird flu vaccination. Immunizations for poultry are in development, and field trials to test a new vaccine in dairy cattle have been ongoing since last year’s outbreak.
NYSDAM also monitors sick poultry and urges New Yorkers to report ill birds by calling 518-457-3502. Dead wild birds — especially in flocks — should be documented by submitting the NYSDEC Avian Influenza Reporting form, available online. Suspected bird flu in cattle or other animals should be reported to your local veterinarian or to a state animal health official. Dutchess County Communications Director Colleen Pillus told the Herald that state agencies currently handle all bird flu issues: “The county would get involved if we had any human cases, but thankfully, there haven’t been any.”
For more information about bird flu, visit the New York State Health Department’s website.