About Bubonic Plague

Bubonic plague is the most common form of plague caused by a dangerous bacteria infection caused by Yersinia pestis. It is transmitted when fleas inhabiting infected rats bite humans. Bubonic plague attacks the lymphatic system; other forms of plague include septicemic plague and pneumonic plague, which attack the blood and lungs, respectively. Although all forms of plague are rare today, cases still occur throughout most parts of the world, including the United States.

Geography

• According to the Centers for Disease Control and Prevention, between 1,000 and 2,000 cases of bubonic plague occur throughout the world each year. The disease does not occur in Australia or Europe, but most other regions are affected. In the United States, an average of 10 to 15 people become infected with bubonic plague each year. Most cases in the U.S. have been in the southwestern region, particularly in New Mexico and Arizona, although cases have also occurred in California, Nevada and Colorado.

Effects

• Symptoms of bubonic plague typically occur a few days after exposure, although the disease may not be evident for up to eight days. The first symptom to appear is usually an enlarged, very painful lymph node. This lymph node swelling is called a bubo, and it is from this term the name bubonic plague originates. The first lymph node affected is close to where the person was bitten by an infected flea--most frequently in the groin area. Other symptoms that occur as the disease progresses include fever, chills, fatigue, muscle aches and headache. Occasionally, bubonic plague progresses to the septicemic or pneumonic form of the plague, in which case other symptoms may be present. Symptoms of progressive disease include bleeding from the mouth, nose or rectum, gangrene of extremities, vomiting, symptoms of pneumonia and shock.

Identification

• Bubonic plague is suspected when a person seeks medical care after developing an enlarged, extremely painful lymph node and has been living in very unhygienic conditions. The most commonly performed test used to confirm the diagnosis of bubonic plague involves the aspiration of fluid from the bubo or buboes. The fluid is examined microscopically to determine whether Yersinia pestis is present. If pneumonic or septicemic plague is suspected, fluid from the lungs and blood are also examined.

Prevention/Solution

• Left untreated, between 50 and 90 percent of people who have bubonic plague will die. However, prompt treatment of the condition reduces the mortality rate to 15 percent. Treatment consists of immediate hospitalization in an isolation ward and injected antibiotics. The most effective drugs used in the treatment of bubonic plague are gentamycin and streptomycin. To prevent the spread of the pneumonic form of the disease, people who have been exposed to a person with plague are usually prescribed a short course of oral antibiotics.

Theories/Speculation

• In the 14th century, between 30 and 60 percent of Europe's population succumbed to the epidemic known as the Black Death. The most widely accepted explanation for this event is a widespread outbreak of bubonic plague. It is believed that the plague was brought to Europe from Asia and spread quickly among the population due to poor living conditions of people in this era. Rats were extremely common in homes and workplaces at this time and fleas infested both rodents and humans, allowing the rapid spread of the disease.