An avian flu that has killed millions of birds over the past two years was confirmed in a herd of Montcalm County dairy cows.
This is the first time the virus has infected Michigan cattle.
“It’s been a rapidly evolving situation,” said Michigan Department of Agriculture & Rural Development Director Tim Boring.
The infection stems from a herd of Texas cattle that were brought to a Michigan commercial farm on March 7. State Veterinarian Nora Wineland said the cattle were “perfectly healthy” at the time and passed all veterinary inspections. When the first animal got sick on March 20, samples were submitted to the state lab.
Results confirmed Tuesday, March 26 it was the highly pathogenic avian flu. Further testing established it came from Texas.
Related: A deadly bird flu raised egg prices. Michigan farms vigilantly protect flocks.
The U.S. Department of Agriculture reported this week that the avian flu had spread to dairy cows in Texas and Kansas through wild birds. Health officials say the risk to the public remains low because there has been no change in the virus that would make it transmissible to humans.
“The whole genome sequence has been looked at by both us on the animal health side as well as our colleagues on the public health side,” Wineland said. “They say they are not seeing any changes in the whole genome sequence to indicate that it is any more a threat to mammals.”
MDARD did not detail how many Michigan cows were affected.
But Tim Slawinski, director of the Michigan’s Bureau of Food Safety and Animal Health, said officials don’t believe the infection will impact the commercial milk supply.
“There are measures in place to prevent this type of thing from being a threat to the supply – measures both at the farm level in terms of keeping milk from unhealthy cows out of the supply but also at the processing level,” he said.
Dairy farms are required to divert or destroy any milk from infected animals. State and federal pasteurization requirements are also “proven to inactivate bacteria and viruses” in milk, according to the USDA.
More than 82 million birds have died since a deadly strain of the avian flu started spreading around the globe in January 2022 – making it the deadliest bird flu in U.S. history. It also caused egg prices to soar last year.
Related: A chicken started gasping for air. Three days later, more than 60 birds were dead.
Wild birds carry the virus that can then infect backyard and commercial flocks. The flu spreads easily through contact with infected poultry, equipment, and on the clothing and shoes of farmers. Nearly 118,000 birds have been infected in Michigan at three commercial farms and 25 backyard flocks.
One infected bird means the U.S. Department of Agriculture requires the entire flock to be “depopulated,” or killed, to keep the flu from spreading. It’s particularly deadly for chickens with a 90% to 100% mortality rate, according to the U.S. Centers for Disease Control.
Infected cattle do not need to be depopulated.
“Cattle recover from this,” Wineland said. “Depending how quickly they’re noticed to not be doing well, the recovery window is either fairly short, a few days, up to a little bit longer.”
The avian flu has been detected in other mammals like foxes, raccoons and skunks.
Federal and state agencies are doing additional testing for the bird flu and conducting genome sequencing of infected animals.
“We’re learning more about this virus and what caused it to get into cattle after more than two years of not seeing that,” Wineland said.
The risk of humans getting sick from the avian flu remains low, according to the CDC, and no infected birds will enter the food chain.
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Rachel Carter is a health and wellness expert dedicated to helping readers lead healthier lives. With a background in nutrition, she offers evidence-based advice on fitness, nutrition, and mental well-being.
