University of Wyoming Extension News

Plague found in Jackson-area mountain lions

Mountain lion hunters and the owners of domestic cats in Jackson and the Greater Yellowstone Area are urged to protect themselves and their animals against the plague, according to the University of Wyoming’s Wyoming State Veterinary Laboratory (WSVL).

A mountain lion and her kitten found dead this fall near Jackson have tested positive for the plague, said Ken Mills, a professor in the UW College of Agriculture’s Department of Veterinary Sciences, which manages the WSVL.

Mills said hunters skinning an animal with the plague are susceptible to the disease as are owners of domestic cats stricken with the disease. Cats can contract the plague by eating an infected rodent or by being bitten by fleas from an infected host.

The two mountain lions, along with a third mountain lion that died from the plague earlier this year in the Greater Yellowstone Area, were part of Beringia South’s Teton cougar project. The Kelly, Wyo.-based nonprofit research and educational organization is studying the habits and population of mountain lions in the area and their relationship to wolves.

A fourth cougar that died of the plague last year in the area was part of a study by the Wildlife Conservation Society. It was a 10-year-old female in excellent condition, said Cynthia Tate, assistant veterinarian for the Wyoming Game and Fish Department.

Tate said Beringia South and the Wildlife Conservation Society have collared a number of mountain lions, including the four found dead.

“The interesting thing about the latest finding is that the mother and one of her kittens died from the plague, but the other kitten is doing fine,” Tate said. “We don’t know if the other kitten was exposed and survived. A question that intrigues me is how many exposed cougars actually get sick, and what is the ultimate outcome? What is the proportion of sick cougars that die versus those that recover?”

Tate added that both kittens were weaned but were still very dependent on their mother. The kitten that survived was sent to the G&F’s Tom Thorne/Beth Williams Wildlife Research Center at Sybille.

Tate said the biologists who discovered the dead mountain lion and her kitten were potentially exposed to the plague, but they are doing fine.

There have been five cases of humans in Wyoming contracting the disease since 1978, according to the Wyoming Department of Health. They were in Goshen, Laramie, Sheridan and Washakie counties. The 1992 Sheridan County case resulted in death after a man contracted the disease when skinning an infected bobcat.

Tate said finding the plague in animals such as mountain lions and bobcats – and occasionally domestic cats – is not surprising because they eat rodents, and rodents are the typical carriers.

If the plague is localized in the lymph nodes, Mills said, it’s typically not contagious to people. If the disease spreads to the lungs, however, it can cause pneumonic plague, which can be fatal to not only the animal but humans exposed to the animal.

Those who hunt or trap predators can protect themselves when skinning an animal by wearing long rubber or latex gloves, Tate said. They should avoid contact with an animal that appears sick (rough hair coat and/or drainage out of the eyes), and immediately contact the G&F.

Tate cautions that animals having the plague may not appear sick because the disease can kill rapidly.

“This is a very acute disease,” she said. “The most recent female mountain lion that was found dead appeared healthy. She wasn’t skin and bones.”

The incubation period of the plague is between two and six days after exposure, Tate noted. If hunters develop flu-like symptoms within that period, they should call their doctor.

Mills said, “The plague could be a risk to mountain lion hunters, but I see it as more of a risk to the owners of domestic cats allowed to go outside and hunt rodents.”

There have been at least seven unrelated cases of the plague in domestic cats in Wyoming since last year, Mills said. They included four in Laramie County and one each in Albany, Natrona and Teton counties.

“If your cat develops a fever and has swollen lymph nodes, it is definitely time to call a veterinarian,” he said.

A call should first be made to a doctor or veterinarian (instead of walking into an office unannounced) so precautions can be taken to avoid exposing other people or pets to the disease, Mills noted.

Participating in the laboratory workup in this case were Associate Professor Todd Cornish and Laboratory Technician III Amy Boerger-Fields in the Department of Veterinary Sciences.

Information on the plague is available on the WSVL Web site at

Click on 2005, and scroll to Plague under Topic. The release dates are June 30, June 17 and June 13.



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