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Plague, was a term that was applied in the Middle Ages to all fatal epidemic diseases, but now it is only applied to an acute, infectious, contagious disease of rodents and humans, caused by a short, thin, gram-negative bacillus. In humans, plague occurs in three forms: bubonic plague, pneumonic plague, and septicemic plague. The best known form is the bubonic plague and it is named after buboes, or enlarged, inflamed lymph nodes, which are characteristics of the plague in the groin or neck or armpit. Bubonic plague can only be transmitted by the bite of any of numerous insects that are normally parasitic on rodents and that seek new hosts when the original host dies. If the plague is left untreated it is fatal in thirty to seventy five percent of all cases. Mortality in treated cases is only five to ten percent.

History Of The Bubonic Plague
The origin of the bubonic plague is unknown but it may have started in Africa or India. Colonies of infected rats were established in Northern India, many years ago. Some of these rodents had infected traders on the route between the Middle East and China. After 1330 the plague had invaded China. From China it was transferred westward by traders and Mongol armies in the 14th century. While these traders were travelling westward they followed a more northerly route through the grasslands of what is now Russia, thus establishing a vast infected rodent population there.

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In 1346 the disease reached Crimea and found its way to Europe in 1347. The outbreak in Europe was a devastating one, which resulted in more than 25 million deaths-about twenty five percent of the continent’s whole population. After that the plague reappeared irregularly in many European cities until the early 18th century, when it suddenly stopped there. No explanation has ever been given for the plague’s rapid disappearance.

Symptoms and Causes
The first symptoms of the bubonic plague are headache, vomiting, nausea, aching joints and a feeling of ill health. The lymph nodes of the groin or of the armpit or neck suddenly start to become swollen and painful. The pulse and respiration rate of a bubonic plague victim is increased, and the victim will become listless and exhausted. The buboes will swell until they are approximately the size of a chicken egg. If a case is nonfatal than the temperature will begin to fall in about five days, and approaches normal in about two weeks, but in fatal cases death will probably occur within four days.

Yersinia Pestis, an infectious agent is the cause of the Bubonic Plague. Yersina Pestis is a bacteria, which means the cells lack the internal organization of eukaryotic cells. These bacteria cells would contain the membrane but they would not be able to subdivide the inside of the cell. These bacteria cells do not have a nucleus so instead they have a nucleiod that contains genetic material. The two types of bacteria cells are gram-negative and gram-positive. Yersina Pestis is gram negative and that means that antibiotics are less effective on the plague because of a lipopolysaccharide layer over their walls that adds extra protection.

Lymphatic System
The bubonic plague has a major impact on the lymphatic system. The lymphatic system is made up of lymph nodes, lymphatic vessels, lymphoid organs and circulating lymphocytes. Plague victims tend to have large bumps on their bodies which are called buboes. These are actually swollen lymph nodes filled with puss. The spread of the infection causes the lymph nodes to become hard and painful.

The lymph nodes are heavily concentrated in the neck, armpits, and groin. When a person becomes ill these areas will begin to swell because the body needs to make a vast amount of white blood cells to fight off whatever pathogen has entered the body.

To make all parts of the body function properly the electron transport chain is needed. Yersina pestis releases a toxin into the body that obstructs this function from occurring.

Prevention and Treatment
Many preventive measures can be used to reduce the spread of the plague (sanitation, killing of rats, prevention in transport of rats). Individuals who contract the disease are isolated, fed fluids and put to bed. During World War II, scientists using sulfa drugs were able to produce cures of plague.

Since it is a bacteria, the bubonic plague can be treated with antibiotics. Tetracyline, Streptomycin, and Chloramphenicol are three of the antibiotics used to prevent plague. Sometimes, they are even mixed together to form an antibiotic cocktail. The plague can almost always be cured when it is recognized fast enough.

Since the late 19th century bubonic plague vaccinations have been in use. There is a vaccine that can be taken in a six to month installment period, but there is a element of risk to this vaccination. This vaccination has been proven to be ineffective with people younger than eighteen and older than sixty. The side effects of this vaccination can sometimes result in death and therefore it is not a good idea to use it.

During the Middle Ages, people did not have a clue as to why the plague was spreading so quickly. But now we know that the bubonic plague is spread by fleas. Yersina Pestis(bacteria) moves its way up to the upper digestive tract of the flea where it breeds and multiplies. The flea must find a new host and when it does the flea drinks its blood and regurgitates the bacteria into the host. This also infects the host. Therefore, the plague can be spread by any rodent or animal who could get fleas.

As soon as the bacteria is regurgitated into the new host, it begins to multiply in lymphatic system and the blood stream. The bacteria attacks the whole body at once by travelling to the spleen, liver, brain, lungs and kidneys.

How was the plague transmitted into England? There is much controversy concerning the exact method by which the plague arrived in England. But it is certain that it arrived via the ports, carried on merchant and Naval ships. However, were the infected fleas carried by the rats in the grain or bales of cloth and cotton, or on the backs of the crew, passengers or returning soldiers? Furthermore, how did the disease spread from the ports to the town and country? Via wild rodents in the countryside, by the rats and fleas in transported freight, or by the fleas on their human hosts?
Although the evidence is mixed and debatable, it is suggested they all played a role. There is evidence to support that plague was caught from baggage and bales of clothes and cloth, as in Eyam in Derbyshire in 1665. There is also existing evidence that human transmission is solely responsible. The spread of the plague across the country was far too rapid to be accounted for by wild rodents in the countryside, and it is human transport which explains its movement along the major trade routes, usually by ship(British port to port), or on main roads and navigable rivers. Nevertheless, it is reasonable to assume that rodent transmission played a part in local village to village contamination.

Affects of the bubonic plague
The bubonic plague struck England in 1665. Since, the occurrence of the plague was so unexpected only 14th century preventive measures could be taken. The homeless people were the first to feel the great effects of the plague. They did not have any money and so when the plague struck them they were basically in a hopeless situation. Even the top physicians were affected by the bubonic plague. Many doctors had to take care of the plague victims and because the plague was contagious, the doctors also caught it. The disease spread rapidly amongst family.

To try to prevent the outbreak of the plague the people began to burn fires in the streets to keep the air clean. Fires were also struck in sickrooms to destroy the clothing of deceased victims. They were also killing cats and dogs, because they were believed to be the cause of infection.

Affect On Doctors
Most doctors, during the outbreak of the plague were afraid to visit the patients because they did not want to risk the chance of themselves becoming infected by the disease. Many doctors fled the medical houses, while others were accused of killing their patients for money, or charging outrageous fees. The doctors believed that these accusations were based on resentment.

The doctors also thought it was the rats tail which were the cause of the plague but they still did not have solid preventive measures. The doctors even suggested that standing over the latrine with an empty stomach and smelling it for hours was a good remedy to cure the plague.

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