What's Killing Mountain Lions Near Yellowstone? The Plague

Mountain lions tracked by researchers over nine years in Yellowstone National Park showed evidence of infection by the bacteria Yersinia pestis, which was the cause of the bubonic plague in the mid-1300s.

What's Killing Mountain Lions Near Yellowstone? The Plague

Mountain lions tracked by researchers over nine years in Yellowstone National Park showed evidence of infection by the bacteria Yersinia pestis, which was the cause of the bubonic plague in the mid-1300s.

Twenty million people died in about five years in Europe due to the plague. The bacteria lives in soil, is picked up by rodents and then transmitted by fleas to rodents and other animals. The research project findings were published in Environmental Conservation.

The project was done in the Greater Yellowstone Ecosystem, with antibodies to Y. pestis discovered in eight of 17 pumas tested by complement-enzyme-linked immunosorbent assay. The organism was detected in 4 of 11 pumas tested after necropsy.

Researchers said it age and gender did not matter in regard to exposure or mortality but acknowledged the sample size was small. Most cases were discovered on the western slope of Colorado in the Four Corners region, known as a plague hotspot. From this, researchers say:

This suggests that: (1) Y. pestis may be present at higher levels in the GYE than previously assumed; (2) plague is a significant source of mortality for local pumas (6.6% of sub-adult and adult mortality); and (3) pumas may be a useful sentinel for potential risk of plague exposure to humans throughout the West. We would also emphasize that hunters and others handling pumas in this region should be made aware of the possibility of exposure.

“You start to get a clear picture of how hard it is to be a mountain lion in Jackson Hole,” biologist and co-author Howard Quiqley tells Mike Koshmrl of Wyoming News. “If you get to be an adult mountain lion in Jackson Hole, you’re a survivor.”

The first plague victims, which were female, were discovered in winter 2006. Non-movement signals from a tracking collar led researchers to the adult and her 3-month-old nearby kitten, which also was dead.

“Everyone assumed it was starvation,” Mark Elbroch, cougar program director of the wildcat conservation organization Panthera, told Jason Bittel at National Geographic. “We were as surprised as anyone to learn that the cats had died of plague.”

Plague isn't new in the western U.S. An average of seven people annually are treated for plague, according to the Centers for Disease Control. The CDC says the Y. pestis hotspots are southern Colorado, northern New Mexico, northern Arizona, California, southern Oregon and western Nevada. Treatment is available but, as you might expect, being infected with plague isn't something to be desired.

Prairie dogs are among the significant species that act as carriers for the bacteria.

"Prairie dogs are one of the major rodent species that serves as a reservoir for plague, and they tend to be west of the 100th meridian" in the United States. For this reason, this line of longitude is sometimes referred to as the "plague line," said Dr. Amesh Adalja, an infectious-disease specialist and a senior associate at the University of Pittsburgh Medical Center's Center for Health Security.




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