the plague.Pandemic outbreaks of the Plague are responsible for more human deaths than any other infectious disease, other than malaria. During the Middle Ages, the Black Death killed between one quarter and one third of Europe’s population. Y. pestis is a gram-negative, facultatively aerobic rod. The bacilli usually have a characteristic bipolar or “safety-pin” shape.

Laboratory indicators:

no gas production -TSI

fluorescent antibody test

Pathogenesis

Y. pestis is primarily a rodent pathogen. Humans and other animals are generally accidental hosts infected via the rat flea, Xenopsylla cheopis. The flea ingests viable cells which then multiply in the intestinal tract. Some of these cells are regurgitated when the flea prepares for its next meal, thereby infecting the next host.

Most cells are phagocytosed or killed by the polymorphonuclear leukocytes of the immune system. However, a few are enveloped by macrophages, which are unable to kill the cells and, in fact, provide protection while Y. pestis re-grows its capsular layer and other virulence antigens.

When transformation is complete, the re-encapsulated organisms break out of the macrophages into the extracellular environment where they are more virulent. Y. pestis travels quickly to the lymph nodes where they become inflamed and hemorrhagic, giving rise to the black buboes of “Bubonic” Plague.

Within hours of initial infection, cells spread to the liver, spleen, and lungs via the bloodstream. Severe bacterial pneumonia develops leading 50-60% of untreated individuals to death. During periods of coughing, scores of viable cells are scattered in the air.

Virulence factors: the V & W antigens of Y. pestis cell walls are protein-lipoprotein complexes that prevent phagocytosis.

Incubation:1-3 days (pneumonic) to 2-6 days (bubonic)

Manifestations

Onset is marked by a high fever. Many victims complain of a general feeling of malaise accompanied by pain or tenderness in the lymph nodes, which may swell forming buboes, a characteristic of Bubonic Plague. Symptoms progress to include convulsions, shock, and hemorrhagic changes in the skin. Cyanosis from the necrotizing pneumonia produce the dark skin at the extremities lending to the term “black death.”

Treatment

Streptomycin, tetracyclines, and chloramphenicol are effective antibiotics, as ß-lactams are not effective. Without treatment, fatality rates are 100% for septicemic or Pneumonic Plague and 90% for Bubonic Plague. With treatment, fatality rates drop to 5-20%. Individuals with Pneumonic Plague must, by law, be isolated. Severe necrosis or dry gangrene of the extremities may appear on those who have survived septic shock.

Prevention

Threat of Plague outbreaks could be virtually eliminated by taking appropriate sanitary precautions. In the United States, a majority of cases occur in the desert southwest where the disease is endemic among wild rodents. A formalin-killed vaccine is available, but it is only recommended for individuals at high risk for exposure.

Bubonic Plague, nicknamed the Black Death. It was carried by fleas that traveled on rats, though there were occasions during which it mutated so that it became airborne.

The nursery rhyme “Ring around the Rosie” is based on the Black Death. The first line, ‘ring around the rosie,’ describes those who contracted the Plague, as they would begin to break out in red sores over their lymph nodes; other villagers (the responsible ones anyway) would then make every effort to prevent the ‘rosie’ from leaving the village and taking the disease with him.

‘A pocket full of Posies.’ Many superstitious cures were believd to ward off the disease, though none actually worked.

‘Ashes, ashes, we all fall down.’ As a general rule, once the Black Death entered a village, the entire village would end up being either wiped out or abandoned. Those who died first would be burned in an attempt to keep the disease in check, often resulting in fires that would consume the entire village because everything was tightly packed and made of wood.

Because religions do not start ALL wars!! Wars always start where there is powers!! Religions are just among the parties who have access to power, but there’s many others that did have powers at this time! Switzerland did fight, because they were a mercenary army, that always followed the one who could pay them, and this was right until the Napoleonic wars in the 19th century! Also at the time, they were great barbarian activities, especially after Genghis Khan foray in the eastern Europes at the turn of the 13th century. Those barbarian activities have change the playgrounds often pillaging cities, forcing others to ally and others to oppose… Such fluid geopolitic dynamic has created various opportunities for the power to move from a place to another… Since everyone was always seeking for more powers… You got plenty of participants!!

The Bubonic Plague! It was caused by the germ called Yersinia pestis.

It is called both Black Death and the Bubonic Plague. Both are right

the Bubonic Plague, carried by rats. Can google more info.

The plague or Bubonic plague or Black Death.

Black Death,di you know hat that is also where the popular song “ring around the rosies” came from?

are you serious a man with an IQ of 20 could easily get that one go read a history book and stop asking trivia that everyone knows

the bubonic plague, commonly known as the black plague