While highly pathogenic avian influenza (HPAI or AI) started as a disease impacting Minnesota’s birds, cases have now been confirmed in bears, skunks and red foxes in the state.
Erik Hildebrand is wildlife health supervisor with the Minnesota Department of Natural Resources based in Forest Lake.
“We have documented that highly pathogenic avian influenza has affected some mammals in Minnesota,” he said. “Black bear, red fox and skunks have tested positive. How they contracted it is unknown. The assumption is they were scavenging on and consumed a bird or other critter that had the virus. You can assume this virus is statewide. Recently there have also been reports of dairy cattle and goats in the state testing positive for the virus.”
Hildebrand said skunks that tested positive for avian influenza were reported because they were “neurologic.”
“They were acting strange and not afraid of people,” he said. “That was concerning. AI causes both upper respiratory symptoms and neurological symptoms.”
Foxes living near poultry facilities were reported to be staggering around and not afraid of people.
“If a person walked up to it, it wasn’t running away,” he said. “Don’t approach sick looking wildlife, but talk to your local DNR about next steps.”
A black bear was also reported as neurologic.
“I was on the team that collected the bear carcass and brought it to the University of Minnesota diagnostic lab for testing,” he said. “It came back as positive for AI.”
He said it is helpful if the person who sees the affected animal can safely take a picture to send to the DNR officer with information about what they observed.
“If it’s next to the highway, the animal could have been hit by a car and that’s why it’s having neurologic symptoms,” he said. “It’s a case-by-case situation. Racoons are also scavengers and could contract the virus through feeding on infected birds.”
Hildebrand said reports from the public of sick or dead wildlife help the DNR discover and monitor diseases.
“We need the public’s help,” he said. “We’re in the early stages of research with this virus. There are 144 different strains of AI virus, and they can affect different species differently.
“It’s an evolving situation. This virus has huge implications for the poultry industry and the economy because Minnesota is one of the top three turkey producers in the nation. That’s a large revenue for the state. Wildlife is a reservoir for the virus, so it’s important for wildlife to be tested to see if there is a mutation, which then could give the poultry industry a heads-up to watch for a new strain of the virus and beef up their biosecurity.”
He said while dairy cows have tested positive for AI, it’s not killing cows.
“That’s the unknown right now, why the virus is not killing cows, but it is killing poultry,” he said. “It’s a good thing we have pasteurized milk because pasteurization kills viruses.”
Birds were the first species impacted by AI.
Hildebrand said that in 2022, upwards of 40% of waterfowl in the state tested positive.
“This past season only about 8% of waterfowl tested positive,” he said. “Species can build up immunity. That’s what we’ve seen with waterfowl. In 2022 we had a high prevalence and it was very lethal. Last year the rate was much lower. The thought is that the young have built up immunities.”
Hildebrand said migratory birds can carry the disease from state to state.
“We also have overwintering swans, ducks and geese who stay in open water in Minnesota all year,” he said.
He said viruses thrive in cool, damp temperatures in the spring and fall.
“When it’s hot and dry, the AI virus goes down significantly,” he said. “Winter also slows down how much virus is on the landscape.”
DNR wildlife staff collect samples during waterfowl banding and in ducks and geese harvested by hunters.
He said as long as a duck or goose is cooked to 165 degrees or more, it is safe to eat.
“The CDC and Minnesota Department of Health have shown the risk to people from this virus is very low,” he said.
“We are responsible for coordinating with all the DNR staff in the state when they have reports of dead birds,” Hildebrand said. “The DNR protocol is to respond to cases of five or more birds that are dead or dying in a localized area within a short time period. In those instances, we’d want to submit the carcasses for diagnostic testing to see what is going on to see if a disease is playing a role.”
He said that residents in the Park Rapids area should notify local DNR wildlife manager Erik Thorson, and he will contact Hildebrand’s department.
“We will give guidance on collecting and facilitating submitting carcasses to the lab and track the test results,” he said. “Only recently dead birds or mammals can be tested.”
He said AI mainly affects poultry, waterfowl and shorebirds.
“There are some corvid species of birds like crows or jays that are scavengers and we have seen the AI virus in those species.”
Routine cleaning of bird feeders once a week with a 10% bleach solution is recommended to help prevent the spread of both viruses and bacteria.
“Anyone with concerns about a cat or dog who may have been in contact with a bird with AI should contact their veterinarian,” he said.
More information is available on the avian influenza webpage through the Minnesota DNR at
https://www.dnr.state.mn.us/wildlifedisease/avian-influenza.html
or by calling or the DNR information center at 888-646-6367.
