In early April, Erica Zuhlke, a wildlife rehabilitation program in Michigan, received two fox kits from Macomb County. They had a high fever and had seizures. One soon died.
Zuhlke thought it might be secondary rodenticide, meaning their mother had eaten a poisoned rodent.
About two weeks later, a St. Clair County fox kit showed the same symptoms. The next day, she saw a fourth case, this time from Lapeer County. She couldn’t save them either.
“That’s when I started to wonder what was actually going on here,” says Zuhlke, who founded the nonprofit Critter Crossing Rehabilitation in Attica, east of Lapeer, in 2018.
In a short time she had three dead foxes from completely different locations.
“That was when I had a kind of brain teaser where I was like, ‘Okay, what if this has to do with the current bird flu pandemic?'”
Her suspicions were recently confirmed.
The Michigan Department of Natural Resources has submitted the three Red Fox kits to the Michigan State Veterinary Diagnostic Lab for “highly pathogenic avian influenza testing.”
All three fox kits were determined to be “non-negative,” DNR spokesperson Ed Golder reported. On Wednesday, May 11, the National Veterinary Services Lab in Ames, Iowa, confirmed they were positive.
The virus was detected in swabs collected from the nose, mouth, throat and brain tissue of all three kits, and a full post-mortem examination was conducted to learn more about this disease in foxes, the DNR reported.
These are Michigan’s first cases of avian influenza in wild mammals, but there have been other cases in North America as well. The Minnesota DNR reported on Wednesday, May 11 that a wild fox there had tested positive. The flu also killed a few young foxes in Ontario, Canada. They tested positive on May 2. One of the kits was found dead and the other showed severe neurological symptoms before dying in a rehabilitation center, according to the DNR.
There were also reports of infected foxes in the Netherlands last year.
“HPAI H5N1 viruses can occasionally be transmitted from birds to mammals, as has happened in these cases, and there may be additional detections in other mammals during this outbreak, but they will likely be isolated cases,” Megan Moriarty, the state veterinarian with the DNR, said in a statement.
“At this point, it’s unclear how the fox sets were infected, but it’s possible they may have been exposed from eating infected birds, such as waterfowl.”
This year’s HPAI strain is more aggressive and has caused more deaths among domestic poultry and wild birds than the previous strain in 2015, the Minnesota DNR reported.
RELATED: Can people catch bird flu through our food supply?
To slow or prevent the spread, the state in Michigan has halted all poultry and waterfowl exhibits at trade shows and other events this week.
On Wednesday, the Michigan Department of Agriculture and Rural Development reported the first cases of bird flu in a commercial poultry operation.
Twelve non-commercial backyard flocks in nine Michigan counties have been infected, resulting in 870 birds, according to the federal and state agricultural departments.
Among wild birds, Michigan has confirmed in 69 cases, according to the DNR. In Canada, these are geese, bald eagles, snowy owls, ducks, swans, and others.
The flu spreads quickly and is almost always fatal in some pets, such as chickens, the DNR reports. Wild birds can be asymptomatic but still carry the disease, sometimes over long distances during migration.
Zuhlke, a licensed veterinary technician who works as a daytime animal controller in Lapeer County, isolated the foxes and stopped taking other animals.
She believes the kittens’ mothers — whose circumstances are unknown but appeared to be fine in some cases — fed on infected ducks. In one location, she saw scattered feathers, and in another location, a homeowner reported seeing a frequent fox carrying dead ducks. Sick or weakened birds can be easy prey, Zuhlke said.
The foxes came to Zuhlke through homeowners who knew how to keep animals in their yards. They saw the kittens lying or grabbing on their belongings.
All but one of the kittens died within 12 hours or less under Zuhlke’s care. She was on anticonvulsants to control their seizures, but there is no treatment for bird flu.
“It’s absolutely devastating to see an animal suffer in such a way,” she said.
Zuhlke named the leftover kit “Leftie” because she initially marked her left ear with nail polish to distinguish her from her sibling. The fox struggled to move at first, but over time it regained mobility and neurological function.
Zuhlke takes care to remain aloof and alien to the animals she cares for, and her intention is always to rescue, rehabilitate and release. She helps the babies of abandoned or orphaned raccoons and opossums and takes in sick or injured adults.
“These animals are meant to live in the wild and to deny them anything other than the wild is quite inhumane,” Zuhlke said.
However, she realized that when the fox bumped into walls and obstacles, the flu left Leftie permanently blind and she cannot be released. She is using her remaining senses well and will be placed and held as an “educational ambassador” at the Howell Nature Center, Zuhlke said.
Zuhlke said it’s nice to know the why, to have her seemingly crazy theory validated. “Wildlife rehabilitation is a constantly moving puzzle… There’s a lot of depth to it, and it’s a really awful feeling not to have an explanation as to why certain deaths happen.”
What this means for other animals is not clear to Zuhlke.
“But hopefully it will help get people like government agencies and other rehabbers to think and be careful about the potential for disease crossover.”
The public health risk associated with HPAI remains low, but the U.S. Centers for Disease Control and Prevention advises people to avoid handling sick or dead wild birds. If it is necessary to move a dead bird, use a plastic bag or shovel and wash hands thoroughly afterwards.
It’s best not to interact with wildlife that appears sick or injured, experts advise.
Zuhlke warned people not to intervene unless they see that an animal appears to be injured or sick. Just finding a baby is nothing to worry about – wild animals don’t abandon their babies.
Anyone who notices anything unusual or unexplained deaths in wild birds or sick, dead, or neurologically abnormal foxes is asked to report the information by:
- Call the DNR Wildlife Disease Laboratory at 517-336-5030.
- Call a local DNR field office to talk to a field biologist.
- Using the DNR’s Eyes in the Field app. Choose the “sick wildlife” notification option.
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