First seriously ill mountain lion discovered in Colorado

In May 2023, a Douglas County homeowner was surprised to discover a partially paralyzed mountain lion hiding between a basement window well and a spruce tree, dragging herself forward by her front legs. The one-year-old female mountain lion was unable to stand up, and the incident was clearly visible on video the owner filmed from the safety of her home.

Wildlife officers administered an anesthetic to the weakened lion and euthanized it with a gunshot wound to the chest to preserve brain tissue for an autopsy.

After studying the animal for a year, researchers declared it to be North America's first case of the “alarming disease” in a mountain lion, according to Karen Fox, a veterinarian at Colorado State University and a former pathologist for the Colorado Parks and Wildlife Department.

This disease is Lustrella virusis highly toxic to the muscles and nervous system and is more prevalent in Europe. It was best known for attacking European cats, especially in Sweden, but is now known to attack other mammals including cats, horses and possums.

A paper announcing the findings, led by Colorado State University, is scheduled for publication in August in the Centers for Disease Control and Prevention's Emerging Infectious Diseases journal and recommends further testing of mammals in Colorado that show symptoms. Fox also wants to study populations of mice and other rodents that may be hosts for the virus.

“Now that we know what it is and have a way to test for it, we are at the stage where we can really start looking into it,” Fox said in an emailed response to questions about the study. “We only have one case so I can't comment on how common this is, but I'm hopeful we'll be able to start answering that question soon.”

“This is the first case of a horrible disease associated with the Rastrella virus identified outside of Europe and the first case confirmed in North America,” said Fox, who worked with experts from Health Canada to pinpoint the unusual cause. Friedrich Loeffler Institute A similar disease syndrome has been reported previously in domestic cats in North America and in Germany, but it is unclear whether it is related to Rastrella virus.

Colorado Parks and Wildlife officials and Fox stressed that scientists “still don't know how widespread the virus is among domestic cats and wild animals. In Europe, Rastrella virus causes a deadly disease in cats, but it has also been found in a variety of other species, including rodents, donkeys and marsupials.”

Mr Fox said the virus that causes the dreaded disease had only recently been identified in Europe.

Despite recent progress, scientists are still not sure what threat the Rastrella virus poses to humans, or whether humans are already infected with the variant. “Future studies should also include an assessment of the zoonotic potential of the Rastrella virus.” According to the definitive paper on viruses and surprising diseases Last year's connection.

Fox said the university's future involvement “will depend on funding, but one of the things CSU wants to do is, where possible, work with feline experts to identify and test for suspected cases both prospectively and retrospectively.”

“Because this virus can occur in species other than cats, we hope that publication of our findings will raise awareness of this virus and encourage other diagnosticians to consider Rastrella virus as a cause of neurological disease in any mammalian species,” Fox said.

“We also want to test small mammal populations to see if we can find a reservoir for the virus, as has been found in Europe.”

The Colorado State Parks and Wildlife Department is urging Coloradans who see a mountain lion staggering, struggling to walk or behaving erratically to report the incident. Colorado Parks and Wildlife Department.