Unit 1 Great Scientists John Snow defeats “King Cholera”

(共20张PPT)
Reading
John Snow Defeats
“King Cholera”
一、 什么是霍乱？ ??霍乱是由霍乱弧菌引起的一种烈性肠道传染病，经口感染。
其主要临床表现为腹泻及呕吐等。严重的可发生剧烈的吐泻，
排大量米汤样大便，容易造成严重失水，肌肉痉挛，甚至循环
衰竭而死亡。 二、霍乱是如何传播的？ ??霍乱一般是通过被污染的水、食物及日常生活接触而传播。
例如，由于霍乱菌在酒精中仍可以存活，生吃的醉虾、醉蟹
往往成为传染源；还要注意不喝生水，桶装水最好烧开后饮用。
三、霍乱传播途径 ？ １．经水传播：在霍乱的传播中，水的作用最突出，水源易被
病人吐泻物和污物所污染，易感者既可因直接饮用生水而感染，
也可通过食物、餐具的污染而感染。 ２．经食物传播：霍乱弧菌在食品上存活时间可达１－２周
或更长，条件适宜时还可以繁殖，故食物被污染可形成食物型
爆发、流行。 ３．经生活接触传播：霍乱也可经接触被污染的物品而传播，
特别是手的污染更易导致感染，接触传播多在人员密集、卫生
条件差的情况下发生。 ４．经苍蝇传播：夏秋季苍蝇活动频繁，易将病菌带到食物上，
起一定的传播作用。
It infects people’s intestines(肠道), causing
diarrhoea(腹泻), vomiting(呕吐) and
dehydration(脱水)
Many deaths in African countries in 2005
and even now
5oo deaths in 10 days in 1854 in London.
2010年10月，海地霍乱疫情肆虐210人丧生
1. Skimming
1). What’s the main idea of the passage
John Snow was a well-known doctor in London.
The cause of Cholera was polluted water.
The source of all drinking water should be examined.
How John Snow collected, analyzed data and found the cause of the disease and solved it .
Para 1:
Para 2:
Para 3:
Para 4:
Para 5:
Para 6:
Para 7:
★Find out the topic sentence of each para.
He knew that cholera would never be controlled
until its cause was found.
He became interested in two theories that possibly
explained how cholera killed people.
John Snow suspected that the second theory was
correct but he needed evidence.
It seemed that the water was to blame.
Next, John Snow looked into the source of the water for these two streets.
With this extra evidence, John Snow was able to
announce with certainty that polluted water
carried the disease.
Finally “King Cholera” was defeated.
Careful reading
Read the first paragraph carefully,then answer these questions
1. What was the most deadly disease in 19th century Why
2.When could the cholera be controlled
The cholera, because neither its cause , nor its cure was understood.
John Snow knew it would never be controlled until its cause was found.
Para 1: Find a problem—what causes cholera
Para 2: Make a question
Cholera multiplied in the air . A cloud of dangerous gas floated around until it found its victims.
People absorbed it with their meals.
Which theory is correct
Para 3: Think of a method
Collect data on those who fell ill or died
and where they lived.
Para 4: Collect results
with the help of a map
(plot information on a map to find
out where people died or did not
die.)
Para5: analyze the results:
★Find out where they got their water.
★Analyse the water to see if it is the
cause of the deaths.
water pump
handle
Para6 :Find supporting evidence : Find other evidence to support the analysis.
A woman and her daughter
who lived far away but drank
the water also died.
Para7:Draw a conclusion with certainty
The polluted water
carried the disease.
draw a conclusion
find a problem
make up a question
think of a method
collect results
analyse the results
find supporting evidence
Para 1
Para 2
Para 3
Para 4
Para 5
Para 6
para 7
What should we pay attention to in our daily
life in order not to get infected with cholera
Heat the food left overnight
Cook raw food thoroughly
Wash hands often
Keep away from flies
choose fresh sea food
Keep the kitchen clean
Dispose rubbish properly.
Drink boiled water
discussion
Cholera was 19th century disease. What disease do you think is similar to cholera today Why
SARS and AIDS. They are both very serious, have unknown cause and need public health care to solve them.
Homework:
Finish your daily exercises and review what we have learnt this period.