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Wyoming reports rare case of human pneumonic plague

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Posted at 10:23 PM, Sep 15, 2021
and last updated 2021-09-16 00:23:21-04

Wyoming health officials announced Wednesday a "rare but serious" case of pneumonic plague in northern Fremont County, just south of Yellowstone National Park.

Pneumonic plague is the most serious form of plague and the only kind that can be spread from person to person, according to a news release from the Wyoming Department of Health.

Pneumonic plague can be transmitted from inhaling infectious aerial droplets from an infected person, or it can develop through untreated forms of lesser plagues, bubonic plague and septicemic plague.

Symptoms include fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, and sometimes watery or bloody mucous.

Both bubonic and septicemic plague can be transmitted from animals to humans through fleas from infected animals. In the Wyoming case, the infected individual had contact with sick pet cats, according to the Wyoming Department of Health.

Bubonic is the most common form of plague, where patients develop the sudden onset of fever, headache, chills, and weakness and one or more swollen, painful lymph nodes called buboes.

Individuals with septicemic plague develop fever, chills, extreme weakness, abdominal pain, shock, and possible bleeding into the skin and other organs. Septicemic plague can occur as the first symptom of plague or may develop from untreated bubonic plague and can be caused by the bite of an infected flea or the handling of an infected animal.

Wyoming's state health officer, Dr. Alexia Harrist, said the risk for humans to contract plague is very low in Wyoming, but the disease has been documented throughout the state in domestic and wild animals.

“It’s safe to assume that the risk for plague exists all around our state,” Harrist said. “While the disease is rare in humans, it is important for people to take precautions to reduce exposure and to seek prompt medical care if symptoms consistent with plague develop.”

To reduce the risk of plague, WDH recommends:

  • Reducing rodent habitats around the home, workplace, and recreational areas by removing brush, rock piles, junk, cluttered firewood, and possible rodent food supplies.
  • Wear gloves if handling or skinning potentially infected animals to prevent contact between your skin and the plague bacteria.
  • Use repellent if exposure to fleas is possible during activities such as camping, hiking, or working outdoors. Products containing DEET can be applied to the skin as well as clothing.
  • Keep fleas off indoor and outdoor pets by applying flea control products. Animals that roam freely outdoors are more likely to come into contact with plague-infected animals or fleas.
  • If pets become sick, seek care from a veterinarian as soon as possible.
  • Do not allow dogs or cats that roam free to share beds with people.

This human plague case is the seventh thought to be acquired in Wyoming since 1978. Other recorded Wyoming cases include a 1978 out-of-state case acquired in Washakie County, a 1982 Laramie County case, a 1992 Sheridan County case that resulted in death, a 2000 Washakie County case, a 2004 out-of-state case acquired in Goshen County, and a 2008 out-of-state case acquired in Teton County.

Read more about the case here.