Bird flu has reached goats for the first time, a development officials call significant in the nationwide outbreak that began two years ago.
Several baby goats in western Minnesota died earlier this month after being infected with the same strain of avian influenza that has killed millions of birds across the country since 2022, the Minnesota Board of Animal Health announced this week.
While bird flu has found its way to mammals like dogs and skunks before, this is the first time in the United States the virus has been found in a ruminant — a group of animals that includes cattle, sheep and goats.
"It highlights the possibility of the virus infecting other animals on farms with multiple species," state veterinarian Dr. Brian Hoefs said in a statement. "Thankfully, research to date has shown mammals appear to be dead-end hosts, which means they're unlikely to spread [the virus] further."
A backyard flock of 23 chickens and ducks in Stevens County was depopulated in February after the H5N1 highly pathogenic avian influenza (HPAI) was found in the birds. Not long after, the owner reached out to state officials about "unusual deaths of newly kidded goats," which shared the same space and water source as the poultry flock, according to the animal health board.
Five of the 10 goat kids that died, which were all younger than two weeks old, tested positive for bird flu, according to a report filed at the World Organisation for Animal Health.
The U.S. Department of Agriculture is working with the state Board of Animal Health to investigate the transmission.
"The risk to the public is extremely low, and any risk of infection is limited to people in direct contact with infected animals," the board said. "To date, no people in the United States have become ill following contact with mammals infected with this virus."
The larger risk comes from increased animal-to-animal transmission, said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
"The evolution of the virus makes it much more likely to infect other species," he said. "It's not surprising that we're going to see other mammals living close to other species get infected."
But as the virus has mutated since it first appeared in Hong Kong in 1997, it has become less of a threat to humans, Osterholm said. "We're watching this closely, things could change tomorrow, but for now there is low risk for human transmission."
There has not been an outbreak at a commercial poultry farm in Minnesota since late December. Statewide, more than 6 million birds, mostly turkeys, have died from the virus or been culled to prevent its spread since early 2022.
Minnesota is the nation's leading turkey producer, and it lies in a major migration pathway. Scientists say migrating waterfowl are the main source of bird flu transmission. The extremely contagious virus can travel on dust particles for miles through the air, and the virus is present in the fecal matter of infected birds.
Those with backyard poultry flocks are urged to follow strict biosecurity guidelines, especially as the spring migration picks up.
"Animals with weakened or immature immune systems, like the goat kids in this case, are at higher risk of contracting disease," the board said. "Biosecurity is the first line of defense for anyone to protect their animals from disease and includes simple measures like cleaning equipment and housing regularly, separating livestock from wild animals, and calling your veterinarian when animals appear sick."
