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What is plague?

Plague is a disease caused by bacteria (Yersinia pestis) that live in some rodents (e.g., prairie dogs, ground squirrels or rats) and other small mammals (including domestic cats).  The disease can spread to people by the bite of an infected flea or by handling an infected animal.  There are several different forms of the plague disease. 

Who gets plague?

Anyone can get plague, but it occurs most often in people who work with or visit areas where there are infected animals. Plague is very rare in the United States.  Most recent cases have been limited to the western and southwestern states.

How is plague spread?

Plague bacteria live in certain animals, such as rodents and other small mammals.  Fleas feed on these animals and become infected.  The disease may spread to people if they are bitten by an infected flea.  People may also get the disease though close contact with infected animals (e.g., though an animal’s bite or scratch or through handling animal tissues).  If the disease gets into the lungs, it may be spread from person-to-person by droplets released when coughing or sneezing. 

What are the symptoms of plague?

There are three types of plague; fever, chills, headache and rapidly progressive weakness are characteristic of all types.  The most common form is bubonic plague.  In this form, patients develop a swollen painful lymph node in the area an infected flea bit the person.  Pneumonic plague is uncommon, but the most serious form of the disease.  It is characterized by high fever, cough with bloody or watery sputum and difficulty breathing.  Septicemic plague (bloodstream infection) can occur as a complication of bubonic or pneumonic plague or from flea bites or direct contact.  It is characterized by abdominal pain, shock and bleeding into the skin and other organs.

How soon after infection do symptoms appear?

The symptoms may appear anywhere from 2-6 days after exposure.

How is plague diagnosed?

Special laboratory tests can be used to diagnose plague. Samples may be taken from the swollen lymph node, blood, spinal fluid or other body sites.

What is the treatment for plague?

Typically, a patient with suspect plague diagnosis should be hospitalized and isolated.  Antibiotics should begin as soon as possible after appropriate specimens are taken for testing.  Persons who have been in close contact with a case of pneumonic plague should be identified and evaluated. 

How can plague be prevented?

Travelers to areas where plague occurs should avoid contact with rodents and fleas, avoid handling sick, dead or stray animals, and keep away from rodent infested places. Rodents and fleas should be controlled where the disease has occurred.  Persons with plague and their belongings should be treated to kill all fleas.  Persons with pneumonic plague should be isolated in the hospital on airborne precautions until 48-72 hours after antibiotics have been started.  Close contacts should also be treated with antibiotics and watched for any signs of illness.

Is there a vaccine for plague?

The vaccine for plague was discontinued in the United States in 1999 and is no longer available.

For more information on plague, visit the Centers for Disease Control and Prevention.

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