Bubonic Plague

Bubonic Plague

What is Bubonic Plague?

Bubonic plague is an infectious disease caused by the bacteria Yersinia pestis. People mostly acquire plague when they are bitten by a flea that is infected with the plague bacteria. The Bubonic plague bacteria are found mainly in rodents such as rats, squirrels, and rabbits. The risk of plague is highest in areas that have poor sanitation, overcrowding and a large population of rodents.

Bubonic plague is the most common form of plague and results in swollen and tender lymph nodes called “buboes” in the groin, armpits or neck giving it the name Bubonic plague. The Bubonic plague was once called “The Black Death” as it caused the deaths of millions (about 30 to 60% of the population) in Europe in the thirteenth century.

There are three forms of plague: Bubonic plague (when lymph nodes are affected), Septicemic plague (when the blood is infected) and Pneumonic plague (when the lungs are infected).

When a person becomes infected with the bacteria that cause Bubonic plague, the bacteria begin to multiply within the lymph system, and the symptoms may start occurring after one to seven days. If they are not treated quickly, the symptoms can rapidly worsen and result in death. The Pneumonic form is invariably fatal unless treated early.

Today plague occurs in fewer than five thousand people a year worldwide.


What are the Causes of Bubonic Plague?

People acquire plague when they are bitten by a flea that is infected with the plague bacteria, bites or scratches from infected animals or if people come into contact with infected tissues or body fluids of an infected animal's blood, handling an animal that is sick or that has died from the plague.

You can also acquire plague by the inhalation of respiratory droplets of a patient with Pneumonic plague. The septicemic and pneumonic forms are very serious and contagious conditions which can trigger severe epidemics with very high fatality rates.

Causes of Bubonic Plague

What are the Signs and Symptoms of Bubonic Plague?

The signs and symptoms occur one to seven days after being infected by the bacteria Yersinia pestis. Patients develop flu-like symptoms such as sudden onset of fever with chills, nausea, headache, abdominal pain, muscle pain, general weakness, and diarrhea. There are swollen, tender and painful lymph nodes (called buboes) under the arms, in the neck, the groin or site of the insect bite or scratch. The bacteria multiply in the lymph node closest to where the bacteria enter the human body. These inflamed lymph nodes may end up turning into pus-filled open sores, and if the patient is not treated with appropriate antibiotics, the bacteria can spread to other parts of the body.


Approximately 10 to 20 percent of people with Bubonic plague symptoms may develop Pneumonic plague symptoms that can often be fatal.

Septicemic plague: Bubonic plague symptoms can progress rapidly to septicemia. This condition occurs when the bacteria that cause plague invades the bloodstream causing fever with chills, weakness, shock and bleeding into the skin. Also, the internal bleeding may cause spots on the skin that are red at first due to pooling of blood under the skin which later turns black giving the skin a black color.

Septicemic plague can occur as the first symptom of plague or may develop from the untreated Bubonic plague. Bubonic plague can advance and spread to the lungs, which is the more severe type of plague called Pneumonic plague.


Pneumonic plague: Ten to twenty percent of people with Bubonic plague develop symptoms in the lungs such as a cough, shortness of breath, chest pain, sometimes bloody or watery mucous and rapidly developing pneumonia, fever, rapid and difficult breathing, respiratory failure or acute respiratory distress syndrome. Any person with Pneumonic plague may transmit the disease via droplets to other humans. Untreated Pneumonic plague has a very high fatality rate.

When Bubonic plague is fatal in 30-60 percent of cases, the mortality rate is 75 percent for Pneumonic plague.

Symptoms and Signs of Bubonic Plague

How do you Diagnose Bubonic Plague?

Laboratory tests include identifying the bacteria Yersinia pestis from a sample of pus from your swollen lymph nodes, bubo, blood or sputum. Detection of specific Yersinia pestis bacteria antigen is also diagnostic of Bubonic plague infection.

Diagnosis of Bubonic Plague

What is the Treatment for Bubonic Plague?

When infection with the Yersinia pestis bacteria is suspected, the person is often hospitalized and placed in isolation. The treatment of bubonic plague is started immediately even before the diagnosis is confirmed as the disease progresses rapidly. With no treatment, Bubonic plague can multiply in the bloodstream or the lungs and may result in death within 24 hours after the appearance of the first symptom.

Plague can be successfully treated with antibiotics such as Streptomycin, Gentamicin, Doxycycline, Aminoglycosides, Tetracyclines, Fluoroquinolones, such as Ciprofloxacin, Sulfonamides, and Levofloxacin. With antibiotics, most people get better within a week or two. But without treatment, most people with the plague die.

People with Pneumonic plague should be hospitalized and must be isolated from other patients and may require intravenous fluids, oxygen, and sometimes breathing support. However, people with Pneumonic plague must be treated within twenty-four hours after they develop symptoms as Pneumonic plague is mostly fatal. Also, anyone who has come into contact with people with Pneumonic plague should also be monitored and given antibiotics as a preventive measure.

How do you Prevent Bubonic Plague?

Bubonic plague is highly contagious; hence contacts of patients with plague should be placed under observation and given preventive antibiotic therapy to prevent transmission to others.

Rodent proof your home. Fill holes and cracks in your home to stop rodents such as mice, rats, and squirrels from getting inside the house. Also clean up places near the house such as piles of wood, leaves, and rocks where rodents might make their homes.

Wear gloves. When handling potentially infected animals either alive or dead, wear gloves to prevent contact between your skin and harmful bacteria.

Keep your pets free of fleas. Also, use insect repellent to prevent flea bites when outside the home.

Latest Publications and Research on Bubonic Plague