Michigan reports 3 red fox kits died from highly pathogenic avian influenza

May 13, 2022

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The Michigan Department of Natural Resources received confirmation Wednesday evening that three red fox kits died from highly pathogenic avian influenza – the state’s first such confirmation of the HPAI virus in wild mammals. The fox kits, collected between April 1 and April 14, came from three separate dens in Lapeer, Macomb and St. Clair counties.

The DNR had received a report from a wildlife rehabilitator in southeastern Michigan about the fox kits exhibiting neurologic signs of HPAI before death. The kits were observed circling, tremoring and seizing. Two of the three died within hours of intake, while one appeared to respond to supportive therapy but then died in care. Interestingly, an additional kit that was a sibling of the Macomb County kit did survive, but developed blindness, making her non-releasable. This kit will be housed at a local nature center.

These cases in Michigan are not the first confirmed detections of HPAI in red foxes:

A recent article in Emerging Infectious Diseases demonstrated H5N1 virus detection in wild red fox kits at a rehabilitation center in the Netherlands in May 2021, during an outbreak of HPAI in wild birds.
In North America, the first report of HPAI H5N1 in wild mammals occurred in Canada May 2, 2022, when two wild fox kits in Ontario tested positive for the virus. One of the kits was found dead and the other displayed severe neurologic signs before dying at a rehabilitation center. Virus was detected in brain tissue, and sequencing results indicate that it is the same strain of HPAI found in the current North American outbreak (H5N1 A/goose/Guangdong/1996 (Gs/GD) lineage).
The Minnesota Department of Natural Resources on Wednesday reported that state’s first confirmed case of HPAI in a wild mammal, a wild fox kit from Anoka County.

“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,” said Megan Moriarty, the state wildlife veterinarian with the DNR. “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.”

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Highly pathogenic avian influenza is a virus known to affect birds throughout North America, with detections in backyard flocks and commercial poultry facilities, to date, in 34 states and detections in wild birds in 35 states. HPAI is highly contagious and poultry are especially vulnerable. In addition, this viral strain also affects waterfowl, raptors and scavengers (like turkey vultures, eagles and crows).