Plaque map

When you wonder what the cat dragged in, you might expect a dead mouse or bird. But one house cat in Sheridan brought home something much worse; plague.

Bubonic plague, to be precise; the pathogen responsible for several historic pandemics including the Black Death that wiped out about 60 percent of the population of Europe in the 14th century. 

“Plague is a serious bacterial infection that can be deadly for pets and for people if not treated as soon as possible with antibiotics,” said Dr. Alexia Harrist, Wyoming state health officer and state epidemiologist with the Wyoming Department of Health. “The disease can be transmitted to humans from ill animals and by fleas coming from infected animals. We want people to know of the potential threat in the cat’s home area as well as across the state.”

Plague is extremely contagious with a high mortality rate if left untreated. What made plague so frightening in the past is that the method of transmission was unknown; and there was no known treatment. Today, we have both unknowns covered, 

Where plague comes from

According to the Centers for Disease Control, plague is caused by a bacterium called Yersinia pestis that often infects small rodents (like rats, mice, squirrels or prairie dogs) and is usually transmitted to humans through the bite of an infected flea.

Pneumonic plague, a particular form of plague infection, is instead transmitted through infected droplets in a sick person’s cough.

The Wyoming Department of Health reports that human plague is rare in Wyoming with just 6 cases reported since 1978. In the United States plague has occurred as mostly scattered cases in rural areas (an average of 10 to 20 persons each year). Globally, the World Health Organization reports 1,000 to 3,000 cases of plague every year. 


A person usually becomes ill with bubonic plague 2 to 6 days after being infected. The typical sign of the most common form of human plague is a swollen and very tender lymph gland, accompanied by pain.

The swollen gland is called a “bubo” (hence the term “bubonic plague”). Bubonic plague should be suspected when a person develops a swollen gland, fever, chills, headache, and extreme exhaustion, and has a history of possible exposure to infected rodents, rabbits, or fleas.

When bubonic plague is left untreated, plague bacteria invade the bloodstream.

When plague bacteria multiply in the bloodstream, they spread rapidly throughout the body and cause a severe and often fatal condition. Infection of the lungs with the plague bacterium causes the pneumonic form of plague, a severe respiratory illness. The infected person may experience high fever, chills, cough, and breathing difficulty, and expel bloody sputum.

If plague patients are not given specific antibiotic therapy, the disease can progress quickly and result in death.


According to the Wyoming Department of Health, a patient diagnosed with suspected plague should be hospitalized and medically isolated.

Laboratory tests should be performed, including blood cultures for plague bacteria and microscopic examination of lymph gland, blood, and sputum samples.

Antibiotic treatment should begin as soon as possible after laboratory specimens are taken. Streptomycin is the antibiotic of choice. Gentamicin is used when streptomycin is not available. Tetracyclines and chloramphenicol are also effective.

Persons who have been in close contact with a plague patient, particularly a patient with plague pneumonia, should be identified and evaluated.

The U.S. Public Health Service requires that all cases of suspected plague be reported immediately to local and state health departments and confirmed by CDC officials. As required by the International Health Regulations, CDC reports all U.S. plague cases to the World Health Organization.

(0) comments

Welcome to the discussion.

Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.