First U.S. Case of Fatal Brain Virus Found in Colorado Mountain Lion

A devastating and lone precocious discovered microorganism has present been recovered successful America’s chaotic cats. In a caller lawsuit report, scientists and wildlife officials successful Colorado papers the archetypal known U.S. corruption of rustrela microorganism successful a upland lion. The germ causes an usually fatal neurological unwellness successful cats called staggering disease.

In May 2023, Colorado Parks and Wildlife officials were notified of a sickly chaotic upland lion that had recovered its mode to a residential country successful Douglas County, Colorado. The upland lion’s hind legs had mostly gone limp, meaning that the feline moved chiefly by dragging itself with its beforehand legs. Officials archetypal tranquilized and past euthanized the carnal with a gunshot to the thorax successful bid to support its encephalon intact for further study.

A video of the sickened upland lion captured by a homeowner successful the area. Credit: Fox, et al/Emerging Infectious Diseases

Early tests failed to find different known germs that tin origin terrible encephalon infections successful cats, specified arsenic the rabies microorganism oregon Toxoplasma gondii. But a elaborate familial investigation of the cat’s encephalon and spinal insubstantial yet revealed the beingness of rustrela virus, formally known arsenic Rubivirus strelense.

Rustrela was lone discovered respective years ago. In October 2020, researchers detailed uncovering it successful animals residing astatine a German zoo that had travel down with neurological problems. Months earlier the lion death, successful February 2023, scientists elsewhere published probe appearing to corroborate rustrela arsenic the origin of staggering disease.

While rare, staggering illness has been known to sicken domesticated and chaotic felines passim Europe since the 1970s. This caller case, detailed Thursday successful the diary Emerging Infectious Diseases, is the archetypal confirmed study of rustrela microorganism and staggering illness among cats successful the U.S. 

At this point, determination is overmuch we don’t cognize astir the information it poses to cats and different animals. The microorganism isolated from the upland lion is reasonably genetically chiseled from the variants seen successful Europe, for instance, leaving unfastened the anticipation that it’s already endemic successful parts of the U.S. Rustrela besides seems susceptible of infecting a wide assortment of mammals, but it’s chartless whether it could perchance marque radical sick. It is simply a adjacent relative of the microorganism that causes rubella successful humans, which tin rarely origin neurological illness, peculiarly successful babies who are infected successful the womb. Rubella has been eliminated successful the U.S. since 2004 acknowledgment to a highly effectual vaccine and wide puerility vaccination program.

“Considering its wide big scope successful Europe, rustrela microorganism should beryllium considered arsenic a origin for neurologic diseases among mammal taxon successful North America,” the researchers wrote.

Worrying arsenic this find is, it besides means that scientists tin commencement to excavation further and reply these important questions.

“Now that we cognize what we’re looking for, it should beryllium easier to find caller cases if they are retired there,” said pb study writer Karen Fox, a erstwhile pathologist with Colorado Parks and Wildlife, successful a connection from the agency. “With continued collaboration, we program to larn what we tin from our colleagues successful Europe portion we proceed to look for caller cases of staggering illness present successful Colorado.”

As portion of this effort, residents who travel crossed likewise sick upland lions successful the country are being asked to study their sightings to their section wildlife officers.