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(Pneumonic plague, bubonic plague)
What is plague?
Plague is a potentially severe disease caused by a bacterium, Yersinia pestis. It caused the “Black Death” in Europe during the Middle Ages, when approximately one-third of the European population died. Rats on ships brought plague from China to San Francisco in 1900. Today, it continues to cause disease in wild rodents (for example, ground squirrels and prairie dogs), cats and dogs in the southwestern United States, California and southern Oregon. Plague also exists in eastern and southern Africa, Southeast Asia, China, Russia and parts of South America.
What are the symptoms of plague?
Initial symptoms include high fever, chills, muscle aches, headache, nausea, vomiting, diarrhea, abdominal pain, and extreme exhaustion. Swollen and tender lymph nodes near the spot where the plague bacteria entered the skin are typical of bubonic plague. Pneumonic plague usually presents with fever, cough, bloody sputum and difficulty breathing.
Who are the different kinds of plague?Bubonic (lymph gland) plague: This illness is caused when the plague bacteria enters the skin. This usually is caused by a flea bite. If a flea feeds on an animal that has plague bacteria in its bloodstream, it will carry the bacteria and then transmit the infection if it bites a person. The bacteria travel to the lymph glands (nodes) in the groin, neck or armpit where they multiply and cause tender swellings called “buboes.” This disease also can occur if a person is scratched or bitten by an infected animal, or if an infected animal carcass is handled without gloves and the bacteria enter through a break in the skin. Bubonic plague can be effectively treated with a variety of widely-available antibiotics. As with all plague infections, bubonic plague is a severe illness. If untreated, it can be fatal in approximately 50-60% of infected persons.
Pneumonic (lung) plague: This is a very severe illness. It can occur if a person breathes in plague bacteria that were coughed by an infected animal (e.g., a cat) or another person with pneumonic plague. After entering the lungs, the bacteria multiply and cause life-threatening pneumonia. Pneumonic plague also can develop from bubonic plague if the bacteria enter the bloodstream and are then transported to the lungs. If not treated with effective antibiotics soon after symptom onset, this illness is almost always fatal.
Septicemic (bloodstream) plague: Plague bacteria can enter the bloodstream either through the skin or from the lungs. If bubonic plague is not treated, it can spread into the blood stream from the lymph nodes (glands). Once in the bloodstream, plague bacteria can spread to the brain and cause meningitis. If not treated with effective antibiotics soon after symptom onset, this illness is usually fatal.
Meningeal plague (brain): This severe illness can occur if bubonic, pneumonic or pharyngeal plague spreads to the bloodstream and the plague bacteria are carried to the brain.
Pharyngeal (throat) plague: On rare occasions, a person may swallow food or beverage that contains live plague bacteria. This can lead to a severe throat infection that can spread to the lungs and bloodstream if not treated.
How soon after infection do symptoms appear?
Bubonic plague occurs 1-7 days after the bacteria enter through the skin. Pneumonic, pharyngeal and septicemic plague occur 1-4 days after exposure to the plague bacteria.
Who gets plague?
Human plague is rare in the United States. Infections occur here when persons come into contact with a plague-infected animal and either breathe in bacteria that the animal has coughed, touch an infected animal carcass or skin, or get bitten by a flea that fed on an animal with plague. In 2002, two travelers from New Mexico were diagnosed in New York City with bubonic (lymph gland) plague; however, their infections occurred at home before they flew to New York City.
How is plague spread?
Bubonic plague is usually transmitted by the bite from infected fleas; however, the disease also can spread to people who are bitten or scratched by infected wild rodents and cats, or after skin contact with carcasses of infected animals. Pneumonic (lung) plague is the only type of plague that can be spread from person to person. This can happen if someone with this illness coughs or sneezes on someone else. Pneumonic plague can be similarly caught from animals that have this illness.
Is plague contagious?
Pneumonic (lung) plague is contagious. If someone with this illness coughs or sneezes on someone else, the infection can spread to that other person. The other types of plague cannot spread from person to person.
How is plague diagnosed?
Plague is diagnosed by growing the bacteria from samples of sputum, blood, spinal fluid, or infected lymph nodes (glands). Antibody testing also can be done in some circumstances.
What is the treatment for plague?
A number of widely available antibiotics are usually effective against the plague bacteria. The recommended treatment regimen is 10 days.
Is there a plague vaccine, and how can I get it?
There are plague vaccines under development; however, there is no vaccine that is currently approved for use in the U.S.
How can plague be prevented?
When traveling in areas where plague is common, it is important to avoid being bitten by infected fleas, or having contact with plague-infected animals or persons infected with pneumonic plague. Patients with pneumonic plague are isolated for 3 days after antibiotic treatment has been started. In places were plague naturally occurs, buildings should be rat-proofed, with appropriate storage and disposal of food, garbage, and refuse. Dogs and cats in such areas should be treated with insecticides to prevent flea infestation.
What has New York City done to address the threat of plague?
Many federal, State, and City agencies-including the New York City Health Departmentand has been working together for several years to prepare for the detection and response to a bioterrorist event in New York City. In cooperation with other emergency response agencies, The New York City Health Department has set in place systems that improve our ability to detect and respond to public health emergencies caused by the intentional release of a biological agent.
For more information about plague, visit the CDC website.
Last Updated: December 2011