What is plague?

Plague is an infectious disease of animals and humans caused by the bacteria Yersinia pestis. Widespread epidemics of plague have had an enormous impact on human history: the first recorded plague epidemic began in Egypt in 541 AD and spread throughout Africa, Europe, and Asia killing approximately 50% of the population; the “Black Death” or “Great Pestilence” that began in 1346 was responsible for approximately 50 million deaths in Africa, Asia, and Europe; and the 1855 epidemic that began in China ultimately killed over 12 million people in India & China. Y. pestis is found naturally in rodents (rats, ground squirrels, prairie dogs, and other rodents on every continent except Australia) and their fleas. Plague may be transmitted to humans through the bite of an infected flea. Use of plague as a biological weapon would most likely be as an aerosol of the bacteria, entering the body through the lungs, resulting in what is known as pneumonic plague.

What are the symptoms of pneumonic plague?

  • Initial symptoms are fever, shortness of breath, and sometimes bloody or watery sputum.
  • Nausea, vomiting, abdominal pain, and diarrhea may also occur.
  • Pneumonia progresses to septic shock and death if not treated.
  • The time from inhalational exposure to death in humans before antibiotics were available for treatment was 2-6 days.



Plague Information for the Public Plague Information for Public Health Officials


Related Links

CDC - Plague Page