Plague was known as the Black Death during medieval times, when it killed up to a third of the population of Europe. Currently, plague occurs in fewer than 3,000 people per year worldwide. It can be deadly if not treated promptly with antibiotics.
The organism that causes plague, Yersinia pestis, lives in a variety of small rodents on every continent except Australia. The organism is transmitted to humans when they are bitten by fleas that have previously fed on infected rodents.
The most common form of plague results in swollen and tender lymph nodes — called buboes — in the groin, armpits or neck. The rarest and deadliest form of plague affects the lungs, and it can be spread from person to person.
Plague is divided into three main types — bubonic, septicemic and pneumonic — depending on which part of your body is involved. Signs and symptoms vary depending on the type of plague.
Other signs and symptoms may include:
Pneumonic plague progresses rapidly and may cause respiratory failure and shock within two days of infection. If antibiotic treatment isn't initiated within a day after signs and symptoms first appear, the infection is likely to be fatal.
When to see a doctor
The plague bacteria, Yersinia pestis, is transmitted to humans when they are bitten by fleas that have previously fed on infected animals, such as:
The bacteria can also enter your body if you have a break in your skin that comes into contact with an infected animal's blood. Domestic cats can become infected with plague from flea bites or from eating infected rodents.
Pneumonic plague, which affects the lungs, is spread by inhaling infectious droplets coughed into the air by a sick animal or person.
The risk of developing plaque is very low. Worldwide, only a few thousand people develop plague each year. However, your risk of plague can be increased by where you live and travel, your occupation, and even by some of your hobbies.
The greatest number of human plague infections occurs in Africa. But the largest concentration of infected animals is in the United States — particularly in New Mexico, Arizona and Colorado — and in the former Soviet Union.
Complications of plague may include:
Preparing for your appointment
You're likely to start by going to an emergency room. You may eventually need to see a doctor specializing in infectious disease.
What you can do
Tests and diagnosis
If your doctor suspects plague, he or she may look for the Yersinia pestis bacteria in samples taken from your:
Treatments and drugs
Although no effective vaccine is available, antibiotics can help prevent infection if you're at risk of or have been exposed to plague. Take the following precautions if you live or spend time in regions where plague outbreaks occur:
Last Updated: 2010-08-28
© 1998-2014 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. A single copy of these materials may be reprinted for noncommercial personal use only. "Mayo," "Mayo Clinic," "MayoClinic.com," "Mayo Clinic Health Information," "Reliable information for a healthier life" and the triple-shield Mayo logo are trademarks of Mayo Foundation for Medical Education and Research.
Terms and conditions of use