Learning Strategy: Data work
Topic: Infectious disease
This topic has become "hot" again with the outbreak of H5N1 avian flu in Suffolk.
160,000 turkeys have been culled in a so-far unexplained outbreak of H5N1 bird flu. This shows the problem is not going away.
It is possible that avian flu will transfer to humans. This has happened before, and UK authorities are preparing in case H5N1 crosses over to humans.
So far, 12 people have died of bird flu in Egypt.
Page 1 has been added to this activity to take account of the current situation.
Teachers' notes for the other three pages of the activity follow below:
Flu can be lethal. The 1918 pandemic killed 50 million people. The virus responsible has now been isolated. Scientists are studying what made it so deadly. But what if it escaped? Could we be protected? In this numeracy activity, pupils compare the death tolls in vaccinated and non-vaccinated populations.
Published: 20th January 2005
Reviews & Comments: 14
Pupils will develop their numeracy in a scientific context and will appreciate the value of immunisation.
Try the activity
You will need Acrobat Reader installed to open the activity sheets.
Curriculum link11 - 14 (KS3)
Unit 8C Microbes and disease
Find out about the role of micro-organisms in infectious diseases.
Learn how immunization can protect against microbial infections.
Running the activity
Timing: starter - 5 minutes; main - 15 minutes; plenary - 5 minutes
Starter activity: Pupils can describe symptoms of their worst flu attack and suggest how they might have caught it. The virus is spread chiefly by airborne droplets. Close contact between people in buses, trains and school classrooms increases the likelihood of the virus spreading. Most viruses are shed in the first 3 days of the illness.
Main activity: Page 1 is a stimulus page to be projected. It sets the scene and presents the pupil task. The virus that caused the 1918 flu pandemic has escaped from a lab. Pupils need to help the Health Protection Agency assess the problem. They must learn how a virus spreads and make predictions about death rates with and without mass vaccination.
Page 2 provides all the data needed for the calculations.
This can be projected, or photocopied for each group. Each student will need their own copy of Page 3. It provides a structured template to help them set out their figures.
Teachers may wish to point out that figures like these can only be used to make short-term predictions. Eventually there are no new contacts left in a population. Most people who come into contact with a carrier have immunity already, so the spread of the disease will eventually peter out.
Plenary: Pupils could discuss the problems a flu pandemic would cause. Disposal of so many bodies could be a problem. When BSE hit British farms, the corpses of infected cows were burned in open fires to destroy the virus. Would this be an appropriate way of disposing of infected human corpses?
The figures used in the case study have been simplified to make the calculations more manageable. On average, a flu sufferer will infect only 2 other people. The disease spreads so quickly because each of these new sufferers can infect 2 more people after 3 days. The total mortality in the 1918 flu pandemic was 0.5% of the population. 2% of the people who were infected died. The death rate was highest in the very young and the very old. Mortality was much higher in places where the population had less natural immunity. In Samoa, 25% died and in Alaska, 50% of Eskimos died.
Immunisation only gives total protection from the strains of virus it is designed to combat. It could reduce the chance of a new virus causing an infection, but only if that virus was fairly similar to those expected to be in circulation. The flu jab protects against 3 different strains and only 1 or 2 circulate each year. Usually there is a good match between the vaccine and the strains people are exposed to. Partial immunity would cause a reduction in flu symptoms so it would also reduce the death rate.
- BBC Health News
- 1918 killer flu secrets revealed
- How Stuff Works
- How flu works.
- World Health Organisation
- WHO Influenza Pandemic Preparedness plan
- The news story of February 07
- The news of the death of the Egyptian girl from bird flu
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