Bird flu makes jump to mammals: three baby foxes die in Michigan

Photo of Angela Mulka
FILE - The fox kits, collected between April 1 and April 14, came from three separate dens in Lapeer, Macomb and St. Clair counties.

FILE - The fox kits, collected between April 1 and April 14, came from three separate dens in Lapeer, Macomb and St. Clair counties.

David Kenyon/MI Dept. of Natural Resources

Three red fox kits died from highly pathogenic avian influenza in Michigan, which is the state's first confirmation of the virus in wild mammals. 

The Michigan Department of Natural Resources received confirmation Wednesday evening that the fox kits had died and announced the news in a press release on Thursday.

The fox kits, collected between April 1 and April 14, came from three separate dens in Lapeer, Macomb and St. Clair counties, according to the release.

The DNR received a report from a wildlife rehabilitator in southeastern Michigan about the fox kits exhibiting neurologic signs of avian influenza before death, according to the release. 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," the DNR stated in the release. "This kit will be housed at a local nature center."

The three fox kits were sampled for avian influenza at the DNR Wildlife Disease Lab and submitted to the Michigan State University Veterinary Diagnostic Laboratory for testing. All three kits tested "non-negative" (presumptive positive) on May 6 and were confirmed positive by the National Veterinary Services Lab in Ames, Iowa, on May 11, according to the release. The virus was detected in swabs collected from the nose, mouth, throat and brain tissue of all three kits. A full postmortem examination was conducted to aid in learning more about this disease in foxes.

These cases in Michigan are not the first confirmed detections of avian influenza 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 avian influenza in wild birds. In North America, the first report of the virus in wild mammals was in Canada on May 2, 2022, when two wild fox kits in Ontario tested positive for the virus.

"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 the release. "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."

Avian influenza is highly contagious and spread in a variety of ways from bird to bird and flock to flock, impacting both wildfowl and poultry, along with domesticated birds. The Michigan Department of Agriculture and Rural Development website states symptoms of birds with avian influenza, sometimes abbreviated HPAI, can include:

  • Sudden death
  • Significant drop in water consumption
  • Lack of appetite, energy, or vocalization
  • Drop in egg production
  • Diarrhea
  • Swollen comb, wattles, legs or head
  • Nasal discharge, sneezing, or coughing
  • Abnormal behavior like difficulty walking

To date, the virus has been detected in backyard flocks and commercial poultry facilities in 34 states and in wild birds in 35 states. In Michigan, avian influenza has been confirmed in 69 wild birds, with the outbreak continuing to spread throughout North America. 

Reporting possible cases of avian influenza

For domestic birds: Domestic bird owners and caretakers should watch for unusual deaths, a drop in egg production, a significant decrease in water consumption or an increase in sick birds. If avian influenza is suspected in domestic birds, contact MDARD immediately at 800-292-3939 (daytime) or 517-373-0440 (after-hours).

For wild birds: If anyone notices what appears to be unusual or unexplained deaths among wild bird populations, report these cases to the Michigan Department of Natural Resources by calling the DNR Wildlife Disease Laboratory at 517-336-5030.

More information on avian influenza and how to protect flocks through biosecurity measures can be found on the U.S. Department of Agriculture's website.

The Michigan Department of Agriculture and Rural Development published an advisory on May 10 to stop all bird exhibitions in the state due to the rapid spread of avian influenza.

Highly pathogenic avian influenza primarily affects birds, but it is important to remember that it can be a zoonotic disease — one that has the potential to be transmitted from domestic or wild animals to humans. 

According to the U.S. Centers for Disease Control and Prevention, the public health risk associated with avian influenza remains low but advises people to avoid handling any sick or dead wild birds. If it is necessary to move a dead bird, use a plastic bag or shovel to do so and thoroughly wash your hands afterward.

The Michigan Department of Agriculture and Rural Development also stated that no birds or bird products infected with avian influenza will enter the food chain.

Follow the status of avian influenza in Michigan at Michigan.gov/BirdFlu and Avian influenza updates (Michigan.gov).