Wyoming Detects Rare Human Case of Pneumonic Plague

September 15, 2021

Wyoming Detects Rare Human Case of Pneumonic Plague

The Wyoming Department of Health (WDH) announced today the detection of a rare but serious case of pneumonic plague in a northern Fremont County resident.

Plague is a bacterial infection that can be deadly to humans and other mammals, including pets, if not treated promptly with antibiotics. This disease can be transmitted to humans from sick animals or by fleas coming from infected animals; in this case, the person had contact with sick pet cats.

Plague can also be transmitted from person to person through close contact with someone who has pneumonic plague. Individuals with a known exposure to plague require post-exposure treatment with antibiotics to help prevent illness. WDH is notifying individuals who may need this kind of treatment.

Plague symptoms depend on how the patient is exposed. The most common form is bubonic plague, where patients develop the sudden onset of fever, headache, chills, and weakness and one or more swollen, painful lymph nodes called buboes. This form usually results from the bite of an infected flea. 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. Individuals with pneumonic plague develop fever, headache, weakness, and a rapidly developing pneumonia with shortness of breath, chest pain, and sometimes watery or bloody mucous.

Pneumonic plague is the most serious form and is the only form that can be spread from person to person. Pneumonic plague can develop from inhaling infectious droplets or may develop from untreated bubonic or septicemic plague.

Dr. Alexia Harrist, state health officer and state epidemiologist with WDH, said while the risk for humans to contract plague is very low in Wyoming, 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.