Infectious Diseases 2022

Infectious Diseases 2022

HPAI confirmed in 3 baby red foxes in Michigan

12 May, 2022

The Michigan Department of Natural Resources (DNR) received confirmation 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. 
The three fox kits were sampled for HPAI 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. 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.
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 reported that state’s first confirmed case of HPAI in a wild mammal, a wild fox kit from Anoka County.

* Rijks JM, Hesselink H, Lollinga P, Wesselman R, Prins P, Weesendorp E, Engelsma M, Heutink R, Harders F, Kik M, Rozendaal H. Highly pathogenic avian influenza A (H5N1) virus in wild red foxes, the Netherlands, 2021. Emerging infectious diseases. 2021 Nov;27(11):2960.