Bubonic Plague

Forms of Plague

Humans can display three different forms of plague. Bubonic plague is the most common, causing the [Page 83]vast majority of cases throughout history. It spreads by Yersinia-infected fleas transmitted from rodent to person. Two to six days after bites from infected fleas, individuals show signs of infection. The most characteristic symptom is the appearance of swollen lymph glands, called “buboes,” in the groin, neck, and armpits. Other symptoms include headache, dizziness, vomiting, shivering, sleeplessness, apathy, delirium, and terrible pain in the extremities. Death typically occurs in untreated individuals within a week of the emergence of symptoms. The bubonic form of plague causes death in more than 50 percent of untreated cases.

Septicemic plague can occur when Yersinia pestis enters and quickly multiplies in the bloodstream. It can result from direct fleabites or as a complication of bubonic plague. The bloodstream can be invaded so quickly that a person can die from septicemic plague before the bubonic symptoms even appear. Symptoms of this form of plague include septic shock, meningitis, and coma. Uncontrolled bleeding under the skin can cause black patches. Untreated, the mortality rate is almost 100 percent.

Pneumonic plague is the least common but most fatal form of plague. It is highly infectious and is the only form that can be transmitted human-to-human. It can appear as a complication of bubonic plague. If Y. pestis invades the lungs, severe pneumonia follows. Weakness, shortness of breath, and coughing increase as the lungs fill with fluid. Coughing and spitting produce droplets filled with the highly infectious bacteria, which is easily inhaled by those nearby. Patients who do not receive treatment within hours of the onset of symptoms will not survive. Death can occur within 24 hours of exposure.

Plague in History

There have been three distinct and well-documented plague pandemics in the last 2,000 years, each having a huge impact on human society. The first, called the plague of Justinian, arrived in Constantinople in 542 from either northern India or central Africa. The plague followed trade routes as infected rats hitchhiked on ships of grain being delivered throughout the Mediterranean Sea. Waves of the plague reappeared throughout Europe for 200 years. It is estimated that over 100 million people died.

...