Recently, Haensch et al. (2010) isolated DNA and protein signatures specific for in human skeletons from the people who are dead from black death.They confirm that Y. pestis caused the Black Death and later epidemics.SoBlack Death is bubonic plague.In 2010 a case was reported in Oregon, United States
The story of_black_death
The Story of Black Death
Background Peaking from Europe From 1346-1353 Killed 30% of Europe‟s population 25 million people
Why was the disease called„‟Black Death‟‟? one of the symptoms produced a blackening of the skin around the swellings. or buboes The buboes were Red->Dark purple->black People was dead with black spot on their skin.
Symtoms in human the appearance of buboes (or gavocciolos) in the groin, the neck and armpits Buboes oozed pus and bled when opened Red and black spots on their skin acute fever and vomiting of blood aching limbs and terrible pain Most victims(70%) died within 4-7 days after infection
Video about the symtoms http://video.google.com/videoplay?doc id=9213528526753799697
Did Black Death happenagain? Yes! The most recent case was reported in Oregon, United States in 2010 They confirmed that Y. pestis caused the Black Death and later epidemics. Black Death is bubonic plague(鼠疫).
How Black Death spread? Black rat, Rattus rattus Oriental rat flea, Xenopsylla cheopis Human flea, Pulex irritans Yersinia pestis
Rats Rodents Maybe direct diseases carrier (including Weils disease, rat bite fever, cryptosporidiosis and hantavirus pulmonary syndrome.) The original carrier for the plague- infected fleas was the black rat
Black rat, Rattus rattus Originated in tropical Asia, then to Near East Spread across the world with European during trading oversea Lives in close proximity to humans Certain resistant to the plague Die-off enhance the transmission
Fleas Acquire Y. pestis by feeding an infected animal Flea‟s digestive tract contain certain protein that is important for survival of Y. pestis Y.pestis aggregate and cause starvation and regurgitation of blood Flea also change its host after infection
Yersinia pestis Rod- shaped, Gram- negative and non-motile bacteria Resist phagocytosis and even reproduce inside phagocytes and kill them.
Bubonic plague: an enlarged, infected lymph nodes called buboes Septicemic plague: occurs when plague bacteria multiply in bloodstream (complication of bubonic plague) Pneumonic plague: Secondary: occur when the bacteriaspread to lungs(complication of bubonicplague) Primary: inhale infectious dropletscoughed into the air by a person or animalwith pneumonic plague
The end of plague Brown rat, Rattus norvegicus Yersinia pseudotuberculosis Other reasons
Brown rat, Rattus norvegicus Larger Aggressive Pushed the smaller and more mouse-like Black Rat out of buildings, alleys, storage sheds and sewers and almost totally out of existence in the whole world. Is not the host of oriental rat flea
Yersinia pseudotuberculosis “less virulent parasite will replace a more virulent parasite over time” -- Pathology Some rats had acquired resistance to bubonic plague bacteria from exposure to this pathogen Bubonic plague failed to sweep the continent ever again the way it did in the mid-fourteenth century
Other hypothesis Weather: the plague drifted away when winter began Fire: Great London fire killed or drove away the majority of rats and the plague left with them Extensive control measures against rats & their fleas
Can you believe that the BlackDeath can bring someadvantage to human? the descendents of the victims of Black Death will not get AIDS even they are infected by HIV ->due to high level of a gene mutation called CCR5-delta 32
Conclusion Black Death was once deadly and characterized as the horrible crisis in the middle ages Europe. But now, it will never become our nightmare again because we have already investigated all its detail.