black death, bubonic plague, black death marcello
Wesleyan University
The Black Death in Florence (Marcello, 1348).

A Look at the Plague and Its History

November 20, 2010 07:00 AM
by Denis Cummings
Last year a remote Chinese village had an outbreak of the pneumonic plague. The plague has been responsible for three recorded pandemics over the last 1,500 years and affects 1,000 to 2,000 people annually.

Pneumonic Plague Kills Three in Chinese Town

In August 2009 an outbreak of pneumonic plague occurred in a remote farming town called Ziketan in China’s Qinghai province. Chinese government officials quarantined the area and started killing rats and fleas, which carry the bacteria that causes the plague.

Pneumonic plague is the most deadly of the three forms of plague. It is caused by Yersinia pestis, the same bacteria that causes bubonic plague, which is assumed to be responsible for the famous “Black Death” plague that devastated 14th century Europe.

Though many assume the plague is a relic of the Middle Ages, there have been continual outbreaks and one pandemic that continued well into the 20th century. The plague remains active in Africa, Asia and the Americas, primarily in remote areas.

In the United States, about 10 to 15 people are infected with the plague each year. About one in seven die. In June, an 8-year-old New Mexico boy died from the bubonic plague, the first recorded plague case in the U.S. this year.

What Is the Plague?

The plague is one of the oldest diseases known to man. It is caused by the bacterium Yersinia pestis, which is carried by fleas and small animals such as rodents.

“There are diseases circulating like this in the world’s rodents, and in many cases having very little impact on them,” University of Liverpool ecology professor Mike Begon told the BBC. “You could only get rid of plague if you got rid of all the rodents, and you are never going to do that.”

There are three forms of the plague. The bubonic form, the most common form, is spread to humans through flea bites and infects the lymph nodes. In serious cases, the bubonic plague can cause one of the other two more deadly forms to develop.

The septicaemic form occurs when the bacteria enters the blood stream, either through a bite or through contact with infected animals.

The pneumonic form affects the lungs. It is spread through the air and can pass from human to human. According to the the World Health Organization (WHO), pneumonic plague is the “most virulent and least common form of plague.”

Bubonic plague victims suffer from “a very painful, usually swollen, and often hot-to-the touch lymph node, called a bubo” and flu-like symptoms such as “fever, headache, and general illness,” according to the Centers for Disease Control and Prevention (CDC). The plague requires immediate treatment with antibiotics.

On average, there are 1,000 to 2,000 cases of the plague every year. According to the latest WHO data, in 2003 there were 2,118 cases of the plague in nine countries, resulting in 182 deaths. More than 98 percent of the cases and deaths occurred in Africa, but the WHO warns that the plague remains endemic in the former Soviet Union, the Americas and Asia. The plague is not found in Australia and has not been active in Europe since World War II.

There are a handful of cases of plague outbreaks in the world every year; the WHO believes that there are others in remote areas that go unreported, and provides a list of recent outbreaks.

History of the Plague

There have been three recorded plague pandemics. The first, known as the Justinian plague, occurred in the 6th century, when the bubonic plague spread through Constantinople and the Byzantine Empire. Though it is difficult to determine the severity of the outbreak due to limited sources, modern historians tend to believe that, at its peak, the plague killed at least 5,000 people a day in Constantinople and killed one-third of its population overall.

The most famous plague epidemic occurred in the 14th century. In 1347, an outbreak of bubonic plague in China reached Sicily by ship; the plague soon spread throughout Italy and Western Europe. Over the next five years, the "Black Death” killed an estimated 25 million people across Europe, about one-third of the population.

Recent scholarship has questioned whether the Black Death was indeed caused by the plague. Several historians and scientists doubt that the bubonic plague, which cannot be spread from human to human, could have spread so quickly through fleas and rodents.

The third pandemic began in China in 1855 and spread to five continents over the next century. It reached San Francisco’s Chinatown in 1900 and spread throughout the city over the next nine years. It was also responsible for an outbreak in Los Angeles in 1924-5, the last major urban outbreak of the plague.

The third pandemic gave scientists a chance to better study the plague. In 1894, physicians Shibasaburo Kitasato and Alexandre Yersin each identified the bacteria Yersinia pestis.

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