In early April, Erica Zuhlke, a Michigan wildlife rehabilitator, received two fox kits from Macomb County. They had high fevers and were having seizures. One soon died.
Zuhlke thought maybe it was secondary rodenticide, meaning their mother had eaten a poisoned rodent.
About two weeks later, a fox kit from St. Clair County presented with the same symptoms. The following day, she saw a fourth case, this time from Lapeer County. She could not save them either.
“It was at that point that I began questioning what was actually going on here,” said Zuhlke, who founded in 2018 the nonprofit Critter Crossing Rehabilitation in Attica, east of Lapeer.
In a short period of time, she had three dead foxes from entirely different locations.
“That was when I kind of had that brain blast moment where I was like, ‘OK, what if this is related to the current avian influenza pandemic?’”
Her suspicions were recently confirmed.
The Michigan Department of Natural Resources 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,” reported Ed Golder, DNR public information officer. 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 postmortem examination was conducted to aid in learning 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. The Minnesota DNR reported on Wednesday, May 11, a wild fox tested positive there. The flu also killed a pair of juvenile foxes in Ontario, Canada. They tested positive May 2. One of the kits was found dead and the other displayed severe neurological signs before dying at a rehabilitation center, according to the DNR.
There were also reports of infected foxes last year in the Netherlands.
“HPAI H5N1 viruses may occasionally transmit from birds to mammals, as occurred in these cases, and there may be additional detections in other mammals during this outbreak, but they likely will be isolated cases,” Megan Moriarty, the state wildlife veterinarian with the DNR , said in a statement.
“At this point, it is unclear how the fox kits became infected, but it’s possible that they were exposed by consuming 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 humans contract bird flu through our food supply?
In Michigan, to slow or prevent the spread, the state this week stopped all poultry and waterfowl exhibitions at fairs and other events.
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, affecting 870 birds, according to federal and state agriculture departments.
Among wild birds, Michigan has confirmed in 69 cases, according to the DNR. These have been in Canada geese, bald eagles, snowy owls, ducks, swans and others.
The flu spreads quickly and is almost always fatal in some domestic species 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 by day as an animal control officer in Lapeer County, isolated the foxes and stopped taking other animals.
She believes the kits’ mothers—whose conditions are unknown but, in some cases, appeared good—were feeding on infected ducks. In one location, she saw scattered feathers and in another, a homeowner reported frequently seeing a fox carrying dead ducks. Sickened or debilitated birds might make for easy prey, Zuhlke said.
The foxes came to Zuhlke through homeowners who knew of denning animals in their yards. They spotted the kits lying or seizing on their properties.
All but one of the kits died within 12 or fewer hours in Zuhlke’s care. She administered anticonvulsant medication to control their seizures, but there is no treatment for avian influenza.
“It’s definitely devastating to watch any animal suffer in such a way,” she said.
Zuhlke named the surviving kit “Leftie” because she had initially marked her left ear with nail polish to distinguish her from her sibling. The fox struggled at first to move, but with time regained mobility and neurological function.
Careful to remain detached and foreign to the animals she tends, Zuhlke’s intention is always to rescue, rehabilitate and release. She aids the babies of abandoned or orphaned racoons and opossums and shelters sickened or injured adults.
“These animals are meant to live in the wild and denying them anything but the wild is kind of inhumane,” Zuhlke said.
She realized, however, as the fox bumped into walls and obstacles, the flu rendered Leftie permanently blind and she cannot be released. She utilizes her remaining senses from her well and is to be placed and kept captive as an “educational ambassador” at the Howell Nature Center, Zuhlke said.
Zuhlke said it is nice to know the why, to have her seemingly crazy theory validated. “Wildlife rehab is a constantly moving puzzle… There is a lot of depth involved, and it’s a really awful feeling not having an explanation for why certain deaths are occurring.”
It is not clear to Zuhlke what this means for other animals.
“But hopefully it will help get people like state agencies and other rehabbers thinking and being cautious about the potential for disease crossover.”
The public health risk associated with HPAI remains low, but the US Centers for Disease Control and Prevention advise 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 then thoroughly wash your hands.
It is best not to make contact with wildlife appearing sick or injured, experts advise.
Zuhlke cautioned people not to intervene unless they see an animal appearing to be injured or ill. Simply finding an infant alone is not cause for alarm – wild animals do not abandon their babies.
Anyone who notices what appears to be unusual or unexplained deaths among wild birds or sick, dead or neurologically abnormal foxes is asked to report the information by:
- Calling the DNR Wildlife Disease Laboratory at 517-336-5030.
- Calling a local DNR field office to speak to a field biologist.
- Using the DNR’s Eyes in the Field app. Choose the “diseased wildlife” reporting option.
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