What it is: Plague is a rare contagious, naturally occurring, disease seen in America mostly in the Southwest part of the country.

How it’s spread: Plague is most often transmitted by fleas that become infected with the bacteria Yersinia pestis. Fleas become infected by feeding on rodents, such as chipmunks, squirrels and mice, and other mammals that are infected with these bacteria. Fleas transmit the plague bacteria to humans by biting them. However, the respiratory type of the plague can also be grown and spread by air for use in biological terrorism.

When a person has plague pneumonia, coughing droplets containing the bacteria into air can cause others to become infected. However, people with other types of plague cannot transmit the infection.

Symptoms: With the respiratory form of the plague, people typically experience fever, chills, headache, severe debilitation, rapidly developing shortness of breath, and chest pain. People may also cough up blood. A person usually becomes ill with plague pneumonia 2 to 4 days after being exposed. If plague patients are not given antibiotics quickly, the disease can be fatal.

Treatment: A patient diagnosed with suspected plague should be hospitalized and placed in isolation to protect against spreading the disease to others. Antibiotic treatment should begin as soon as possible. People who have been in close contact with a person who has plague pneumonia may need antibiotics and should contact their health care provider. In Massachusetts, all cases of suspected plague are required to be reported immediately by healthcare providers to local health departments. In Boston, suspect cases of plague should be reported by healthcare providers to Boston Public Health Commission at 617-534-5611.

Vaccination: A very small number of people have received a vaccination against the plague. However, the vaccine does not protect against plague pneumonia and is not generally available to the public.

Exposure and Environmental Cleanup: If Yersinia pestis were sprayed from a pressurized container, it could cause plague pneumonia. The bacteria require a host for its survival, and are destroyed by heat and sunlight. According to the World Health Organization, an aerosol release of the bacteria would become inactive in less than one hour. Since it would take much longer than one hour for the first cases of disease to appear, there would be no need for environmental decontamination in the event of a covert release. Should an outbreak of plague pneumonia occur, the person who is ill, and those in close contact with the person who is ill should wear simple surgical masks to help prevent transmission of the disease.

The information in this section was compiled from the following sources:
http://www.jama.ama-assn.org/issues/v283n17/ffull/jst90013.html
http://www.hopkins-biodefense.org/pages/agents/agentplague.html
http://www.bt.cdc.gov/Agent/Plague/PlagueGen.asp
http://www.cdc.gov/ncidod/dvbid/plague/qa.htm
http://www.acponline.org/bioterro/plague.htm