First North American case of ‘staggering disease’ found in Colorado mountain lion

DENVER ( KDVR ) — Colorado Parks and Wildlife said the first North American case of an often deadly neurological disease was found in a Colorado mountain lion.

In May 2023, CPW officers euthanized a sick mountain lion in Douglas County. Officers said the animal was unable to use its hind legs.

An analysis later found the presence of the rustrela virus, which CPW said was recently identified as the cause of “staggering disease,” a usually deadly neurologic syndrome recognized in domestic cats.

CPW said this case is considered the first evidence of staggering disease in North America.

The findings were published in a new study this week in the “Emerging Infectious Diseases” journal, according to CPW.

Former CPW wildlife pathologist and lead author of the report, Karen Fox, said scientists don’t know how widespread the virus is in domestic and wild cats just yet.

According to CPW, the rustrela virus has been found to cause staggering disease in cats and other species like rodents, donkeys and marsupials in Europe.

“Now that we know what we’re looking for, it should be easier to find new cases if they are out there,” Fox said. “With continued collaboration, we plan to learn what we can from our colleagues in Europe while we continue to look for new cases of staggering disease here in Colorado.”

Veterinarians at Colorado State University and CPW will look for new cases.

If you notice a mountain lion staggering, having trouble walking or behaving abnormally, call your local CPW office to report it.

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