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 bubonicplague and it is named after buboes, or enlarged, inflamed lymph nodes, which arecharacteristics of the plague in the groin or neck or armpit. Bubonic plague can only betransmitted by the bite of any of numerous insects that are normally parasitic on rodents and thatseek new hosts when the original host dies. If the plague is left untreated it is fatal in thirty toseventy five percent of all cases. Mortality in treated cases is only five to ten percent.

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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 theserodents had infected traders on the route between the Middle East and China. After 1330 theplague had invaded China. From China it was transferred westward by traders and Mongolarmies in the 14th century. While these traders were travelling westward they followed a morenortherly route through the grasslands of what is now Russia, thus establishing a vast infectedIn 1346 the disease reached Crimea and found its way to Europe in 1347. Theoutbreak in Europe was a devastating one, which resulted in more than 25 million deaths-abouttwenty five percent of the continent’s whole population.

After that the plague reappearedirregularly 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.The first symptoms of the bubonic plague are headache, vomiting, nausea, aching jointsand a feeling of ill health. The lymph nodes of the groin or of the armpit or neck suddenly start tobecome swollen and painful.

The pulse and respiration rate of a bubonic plague victim isincreased, and the victim will become listless and exhausted. The buboes will swell until they areapproximately the size of a chicken egg. If a case is nonfatal than the temperature will begin tofall in about five days, and approaches normal in about two weeks, but in fatal cases death willYersinia Pestis, an infectious agent is the cause of the Bubonic Plague. Yersina Pestis isa bacteria, which means the cells lack the internal organization of eukaryotic cells. Thesebacteria cells would contain the membrane but they would not be able to subdivide the inside ofthe cell. These bacteria cells do not have a nucleus so instead they have a nucleiod that containsgenetic material.

The two types of bacteria cells are gram-negative and gram-positive. YersinaPestis is gram negative and that means that antibiotics are less effective on the plague because ofa lipopolysaccharide layer over their walls that adds extra protection.The bubonic plague has a major impact on the lymphatic system. The lymphatic systemis 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 areactually swollen lymph nodes filled with puss. The spread of the infection causes the lymphThe lymph nodes are heavily concentrated in the neck, armpits, and groin. When aperson becomes ill these areas will begin to swell because the body needs to make a vastamount 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.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 toSince 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 almostalways be cured when it is recognized fast enough.Since the late 19th century bubonic plague vaccinations have been in use. There is avaccine that can be taken in a six to month installment period, but there is a element of risk tothis vaccination. This vaccination has been proven to be ineffective with people younger thaneighteen and older than sixty. The side effects of this vaccination can sometimes result in deathand 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 spreadingso quickly. But now we know that the bubonic plague is spread by fleas.

YersinaPestis(bacteria) moves its way up to the upper digestive tract of the flea where it breeds andmultiplies. The flea must find a new host and when it does the flea drinks its blood andregurgitates the bacteria into the host. This also infects the host. Therefore, the plague can bespread by any rodent or animal who could get fleas.As soon as the bacteria is regurgitated into the new host, it begins to multiply inlymphatic system and the blood stream. The bacteria attacks the whole body at once bytravelling to the spleen, liver, brain, lungs and kidneys.How was the plague transmitted into England? There is much controversy concerningthe exact method by which the plague arrived in England. But it is certain that it arrived via theports, carried on merchant and Naval ships.

However, were the infected fleas carried by therats in the grain or bales of cloth and cotton, or on the backs of the crew, passengers orreturning soldiers? Furthermore, how did the disease spread from the ports to the town andcountry? Via wild rodents in the countryside, by the rats and fleas in transported freight, or byAlthough 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 andcloth, as in Eyam in Derbyshire in 1665. There is also existing evidence that human transmissionis solely responsible. The spread of the plague across the country was far too rapid to beaccounted for by wild rodents in the countryside, and it is human transport which explains itsmovement along the major trade routes, usually by ship(British port to port), or on main roadsand navigable rivers. Nevertheless, it is reasonable to assume that rodent transmission played apart in local village to village contamination.The bubonic plague struck England in 1665. Since, the occurrence of the plague was sounexpected only 14th century preventive measures could be taken.

The homeless people werethe first to feel the great effects of the plague. They did not have any money and so when theplague struck them they were basically in a hopeless situation. Even the top physicians wereaffected by the bubonic plague. Many doctors had to take care of the plague victims andbecause the plague was contagious, the doctors also caught it.

The disease spread rapidlyTo try to prevent the outbreak of the plague the people began to burn fires in the streetsto keep the air clean. Fires were also struck in sickrooms to destroy the clothing of deceasedvictims. They were also killing cats and dogs, because they were believed to be the cause ofMost doctors, during the outbreak of the plague were afraid to visit the patients becausethey did not want to risk the chance of themselves becoming infected by the disease. Manydoctors fled the medical houses, while others were accused of killing their patients for money, orcharging outrageous fees.

The doctors believed that these accusations were based onThe doctors also thought it was the rats tail which were the cause of the plague but theystill did not have solid preventive measures. The doctors even suggested that standing over thelatrine with an empty stomach and smelling it for hours was a good remedy to cure the plague. Bibliography: