Widely known as the “Black Death,” the disease that killed 50 million people in Europe's Middle Ages, bubonic plague is still with us  — although cases are relatively rare.

Bubonic plague is one of three life-threatening diseases caused by Yersinia pestis (Y. pestis), a bacteria found in small animals and their fleas. If left untreated, bubonic plague can be fatal; however, it can be easily treated with antibiotics.

Causes and Risk Factors of Bubonic Plague

Bubonic plague is caused by Y. pestis, a bacteria transmitted to humans through fleas that have been infected by animals such as rats, mice, squirrels, rabbits, chipmunks, and prairie dogs. Rodents are the main carriers of the bacteria.

Y. pestis can also enter your body if your skin is broken and you come into contact with an infected animal’s blood. The risk of contracting bubonic plague is very low, but it can increase depending on where you live, what you do for a living, and your recreational pastimes.

Rural areas that have a high number of rodents, for example, are at a higher risk for bubonic plague. Cases in the United States are rare but tend to occur in Western and Southwestern states. If you work outdoors or with animals, this could also put you at an increased risk, as can hunting and camping where plague-infected critters live.

Duration of Bubonic Plague

The duration of cases vary. After administration of antibiotics, symptoms usually take two to five days to resolve.
Buboes may remain for several weeks after treatment, possibly longer if you have a severe case or develop septicemic or pneumonic plague.

Prognosis of Bubonic Plague

If untreated, the prognosis is poor, with mortality rates estimated at 50 to 90 percent.
In the United States, the overall mortality rate is 11 percent.

Treatment and Medication Options for Bubonic Plague

Bubonic plague can rapidly get worse and become life-threatening, so your doctor will begin treatment immediately after your diagnosis. The condition requires hospitalization, and if you contract pneumonic plague, you will be isolated in a private room to prevent person-to-person spread.

Medication Options

Bubonic plague can usually be successfully treated with various antibiotics:

  • Garamycin (gentamicin)
  • Levaquin (levofloxacin)
  • Cipro (Ciprofloxacin)
  • Vibramycin (doxycycline)
  • Vigamox (moxifloxacin)
  • Chloramphenicol

Prevention of Bubonic Plague

Unfortunately, there is no vaccine available to protect you from bubonic plague. If you think you’ve been exposed to it, antibiotics can be taken to prevent infection.

You won’t have to be quarantined, but care will need to be taken to ensure that the infection doesn’t spread from you to others through tissue, blood, or other fluids.
In addition, you may want to take the following precautions:
  • Rodent-proof your home. Get rid of areas where rodents may nest, such as piles of brush and firewood. Avoid leaving food where rodents can access it.
  • Wear gloves. If you must handle a potentially infected animal, wear gloves to prevent contact between your skin and the bacteria.
  • Use insect repellent. DEET-containing products can protect you from rodent fleas when you’re hiking, camping, or working outdoors.
  • Keep pets flea-free. Apply flea-control products to your pets regularly.

Research and Statistics: Who Has Bubonic Plague

In the United States, cases of bubonic plague are rare. The CDC reports that in recent decades, in humans, there’s been an average of seven cases of plague a year.Most U.S. cases occur in northern New Mexico, northern Arizona, southern Colorado, southern Oregon, and California.
Bubonic plague can affect people of any age, but 50 percent of reported cases occur in people between 12 and 45 years old. It occurs in both men and women but is slightly more common in men.

Related Conditions and Causes of Bubonic Plague

In rare cases, bubonic plague may cause meningitis, a condition in which the membranes surrounding your brain and spinal cord become infected and start to swell. Symptoms include a headache, fever, and stiff neck. Immediate treatment with antibiotics can prevent serious complications.

Resources We Love

The CDC has detailed and up-to-date information on this and other rare diseases.

With additional reporting by Carlene Bauer.

Editorial Sources and Fact-Checking


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Maps and Statistics: Plague in the United States. Centers for Disease Control and Prevention. November 25, 2019.

Kugeler KJ, Staples JE, Hinckley AF, et al. Epidemiology of Human Plague in the United States, 1900–2012. Emerging Infectious Diseases. January 2015.

Protect Yourself From Plague. Centers for Disease Control and Prevention.

Plague. MedlinePlus. November 3, 2020.

Plague (Yersinia Pestis). Harvard Health Publishing. December 2018.

Dillard RL, Juergens AL. Plague. StatPearls. August 10, 2020.


Bush LM, Vazquez-Pertejo MT. Plague and Other Yersinia Infections. Merck Manual Professional Version. February 2020.


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