Scientists believe a mysterious neurological disorder causing leg weakness in Florida panthers and bobcats is unrelated to the first North American case of “staggering disease” recently identified in a Colorado mountain lion.

A study published earlier this month for the first time identified the rustrela virus, known to cause the usually fatal staggering disease in domestic cats in Europe, in a mountain lion in North America. Wildlife officials had euthanized the Colorado mountain lion last year after a Douglas County homeowner recorded it dragging itself across the ground while struggling to stand on its hind legs.

In Florida, panthers and bobcats impacted by an unknown neurological condition have been afflicted by similar rear-leg weakness. But the fatal condition Florida scientists have called feline leukomyelopathy, or FLM, is not thought to be caused by the restrela virus, Florida Fish and Wildlife Research Institute spokesperson Johnathan Veach said.

“Both this case of staggering disease and the cases of Feline Leukomyelopathy (FLM) Disorder detected in Florida panthers and bobcats are characterized by similar neurologic signs of hindlimb weakness and incoordination,” Veach said. “Multiple potential diseases can cause these neurological signs, and accurate diagnosis relies on further testing.”

Testing to date by the Florida Fish and Wildlife Conservation Commission, including microscopic examination of the brain and spinal cord, “suggest that FLM is unrelated to staggering disease,” Veach said. The restrela virus that causes staggering disease has not been detected in Florida, he said.

Mountain lions, like those found in Colorado, have the largest range of any mammal in the Americas, and are also known as cougars, panthers and pumas. The Florida panther is considered a subspecies of mountain lion and is listed as “critically endangered” under the federal Endangered Species Act.

Over the past 50 years, conservation efforts have saved the Florida panther from the brink of extinction. But since at least 2017, a neurological disorder with no known cause has been spreading through the state’s panther and bobcat population.

In addition to viral, nutritional, bacterial and fungal testing, scientists have also tested for toxins, including rodenticides, pesticides, herbicides and heavy metals, but found no definitive cause of FLM in wild cats, according to Florida Fish and Wildlife.

Videos of Florida panthers thought to be suffering from FLM show the cats staggering and unstable on their hind legs. To date, Florida Fish and Wildlife has observed 32 probable cases of FLM in panthers and 37 probable cases in bobcats. There have been no reports of FLM in domestic cats or wildlife, but scientists are reportedly concerned there could be spillover.

The Colorado mountain lion euthanized last year is the only case of staggering disease that has been identified in North America to date. But Colorado State University and Colorado Parks and Wildlife veterinarians say they are looking carefully for new cases.

Scientists don’t know yet how widespread the restrela virus that causes staggering disease could be in either domestic cats or wildlife populations in Colorado. But in Europe, restrela virus has also reportedly been found in a wide range of other species, including rodents, a donkey and marsupials.

The study that identified the virus in the Colorado mountain lion raised concern about the “remarkably broad range” of other mammals that can be hosts to the restrela virus. It suggested studying small rodents in the state which could be reservoir hosts, or carriers of the virus that don’t experience any negative effects.