1. The Story of Black Death

2. Background
 Peaking from Europe
 From 1346-1353
 Killed 30% of Europe‟s population
 25 million people

3. 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.

4. 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

5. Video about the symtoms
 http://video.google.com/videoplay?doc
id=9213528526753799697

6. Did Black Death happen
again?
 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).

7. How Black Death spread?
 Black rat, Rattus rattus
 Oriental rat flea, Xenopsylla cheopis
 Human flea, Pulex irritans
 Yersinia pestis

9. Rats
 Rodents
 Maybe direct diseases carrier
 (including Weil's disease, rat bite
fever, cryptosporidiosis and
hantavirus pulmonary syndrome.)
 The original carrier
for the plague-
infected fleas was
the black rat

10. 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

11. 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

12. Yersinia pestis
 Rod- shaped, Gram- negative and
non-motile bacteria
 Resist phagocytosis and even
reproduce inside phagocytes and kill
them.

13.  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 bacteria
spread to lungs(complication of bubonic
plague)
Primary: inhale infectious droplets
coughed into the air by a person or animal
with pneumonic plague

15. The end of plague
 Brown rat, Rattus norvegicus
 Yersinia pseudotuberculosis
 Other reasons

16. 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

17. 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

18. 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

19. Treatment
 Antibiotics (nowadays)

20. Can you believe that the Black
Death can bring some
advantage 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

21. 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.

22. Reference
 http://findmeacure.com/2008/07/17/plague/
 http://hospital.kingnet.com.tw/essay/essay.html?category=%C2%E5%C3%C4%A
Fe%AFf&pid=5137
 http://baike.baidu.com/view/70725.htm
 http://en.wikipedia.org/wiki/Bubonic_plague
 http://en.wikipedia.org/wiki/Acral_
 http://www.goodhealthtipsonline.com/2011/03/bubonic-plague-history-cause-
symptom.html
 http://boisestate.edu/courses/westciv/plague/
 http://www.dhpe.org/infect/plague.html
 http://www.themiddleages.net/plague.html
 http://www.middle-ages.org.uk/black-death.htm
 http://boisestate.edu/courses/westciv/plague/05.shtml
 http://terriermandotcom.blogspot.com/2004/08/rats-prevent-plague.html
 http://www.ratbehavior.org/WildRatDisease.htm#Plague
 http://science.nationalgeographic.com/science/photos/plague/#/plague-
today_9445_600x450.jpg