Essay: The Black Death

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The Black Death was one of the most severe plagues in its time.  I am going to talk about the Black Death, which is also known as The Black Plague and The Bubonic Plague.  The main area I will cover is What the affects of the Black Plague was and how is spread.

The presenting symptoms of the Black Death are shivering, vomiting, headaches, giddiness, an intolerance to light, pain in the back and limbs, and a white coating on the tongue.  A fever of between 103 and 106 occurs immediately.  Within 24 hours coughing starts, then becomes spitting up blood. The plague is an acute disease, meaning it normally doesn’t last a long time.  Also, if you recover from having it you will be immune to it for the rest of your life.

The Black Death is caused by the infectious agent Yersinia Pestis, also known as Pasteurella Pestis. Yersinia Pestis is a bacteria.  There are two types of bacteria cells, gram-negative and gram-positive. Yersinia Pestis is gram-negative.  This makes antibiotics less effective on the plague because gram-negative bacteria have a lipopolysaccharide layer over their walls that add extra protection.

The lymphatic system is the system most greatly affected by the Black Death.  Plague victims are notorious for having large bumps on their body called “buboes”. These are in fact swollen lymph nodes filled with puss.  When healthy, the lymph nodes are soft and can’t be easily seen, but the spread of infection causes them to harden and become painful.  They are large and obtrusive, and they sometimes turn black.  This is due to breaking blood vessels, which then dry on the surface of the body, causing black bumps on the body.

The largest concentrations of lymph nodes are in the neck, armpits, and groin.  These epicenters swell when a person is ill because the body makes a large number of white blood cells to fight off whatever pathogen has entered the body. Lymph contains many white blood cells that help fight cancer causing and disease organisms.

The “electron transport chain” function in the body is necessary to make basically all things happen in the body.  Yersinia pestis releases a toxin into the body that inhibits this function from happening. So the bacteria stop the body in its tracks.  This doesn’t involve the lymphatic system, but is another way the plague affects the body.

In the Middle Ages, people weren’t sure how the plague was being spread so quickly.  Now we know that fleas spread the plague.  The bacterium, called Yersinia Pestis, makes its way to the upper digestive tract of the flea where it breeds and multiplies.  When the flea finds a new host and drinks the blood, it regurgitates the bacteria into the host, thus infecting the host.

Many people think that rats spread the Plague.  This is partly true.  Rats are not the direct infectors of the Plague; they are merely hosts for the fleas carrying the bacteria.  The Plague can be spread through any rodent or animal that could get fleas.  So the rat, cat, or prairie dog that has fleas could be considered a vector for the disease.  Rodents can carry the plague, but it does not affect them, they can then pass it on to humans who will most likely die.

Once the bacterium is regurgitated into the new host, it begins to multiply in the blood stream and the lymphatic system.  The Bacterium travels to the liver, spleen, kidneys, lungs, and brain, basically attacking the whole body at once.  The system that the plague has the largest effect on is the lymphatic system, because that is where the most bacteria multiplies.  As the lymph nodes swell with puss, the disease circulates through the blood stream and creates the possibility of hemorrhaging and lots of other things.

The history of the bubonic plague is a sad one.  Three major pandemics have occurred during the 6th, 14th, and 17th centuries.  The first outbreak was known as the Plague of Justinian, named after the Byzantine emperor Justinian.  70,000 people died from the plague in Constantinople over two years.  From there, the plague was transmitted to France and Italy over trade routes, causing small outbreaks for many years.  The effects of this outbreak were on a large scale.

In the 14th century, the worst plague of all time occurred, starting in China. This outbreak became known as the Black Death.  From China, the plague spread to Europe by two routes.  Because China was a major trading center, the plague easily spread on ships.  Also, the Tartars carried the plague closer to Europe and into other trading ports after sieges in Asia.  This outbreak devastated not only Asia and Europe, but also Russia.  The Black Death killed more than 1/3 of the European population, or 25 million people.  Everything in Europe came to a halt during this plague outbreak, but public health institutions were created to deal with stopping the spread of the plague.

The third major outbreak started in Manchuria in 1890.  This plague made its way to San Francisco in 1900.  Many Asian-American citizens were blamed for the plague in the U.S. and were discriminated against because of it.  Houses were burned down if plague victims were thought to live there.  Actions such as this were reminders of the Great Plague of London in 1665.  Less than 20 percent of the population was killed by the Bubonic Plague, but the whole city was burned to the ground in order to stop the outbreak.  This was an extreme measure, but it worked. During the 1980′s, plague cases in the U.S. averaged 18 per year.

Procopius of Caesarea is credited as the first scientist to give a detailed description of the bubonic plague in 541 AD.  Unfortunately, ideas about the causes were filled with false beliefs and superstitions until the late 1800′s.  Both Alexandre Yersin and Kitasato Shibasabaroo discovered the bacillus Pasteurella pestis in their work in 1894.  Pasteurella pestis is the larger group of bacteria that Yersinia pestis, the infectious agent, is part of.  A. W. Bacot then thought of the idea that fleas from infected rats were the carriers of the plague and infected people while trying to draw blood from a bite.  Small grayish spots along with tiny bites helped P. L. Simond prove that fleas were the carriers in 1897.

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