Download 8.1.3.A ChickenpoxOutbreak

Activity 8.1.3 Chickenpox Outbreak
Introduction
An epidemic is an infectious disease that spreads rapidly and sickens a large
number of people. Throughout history, epidemics have had dramatic effects on
human political and social history. The 1918 avian flu outbreak killed an estimated
30-50 million people worldwide and may have been the most devastating shortduration epidemic in history. Other epidemics include smallpox, human
immunodeficiency virus (HIV), which causes acquired immune deficiency syndrome
(AIDS), and severe acute respiratory syndrome (SARS). All of these epidemics are
viral diseases.
Viral diseases are caused by a virus, a sub-microscopic particle that must infect
living plant or animal cells to reproduce. Viruses may spread through a population by
contact with contaminated surfaces, airborne droplets from coughing or sneezing by
an infected individual, or ingesting infected food or water. Prevention of viral
diseases includes vaccines, hand washing, and physical barriers such as covering a
cough or wearing a mask.
A viral disease that used to be common among children in the United States is
chickenpox. The chickenpox illness is caused by the varicella zoster virus (VZV) and
causes an itchy rash of spots that look like blisters and can be accompanied by flulike symptoms such as fever and body aches. Chickenpox is highly contagious and
can be spread by coming in contact with blister fluid of an infected person or when
someone with the virus coughs or sneezes near you. An infected person is
contagious, or can spread the virus, for 1 to 2 days before the rash appears.
In this activity you will model the different ways that a virus such as chickenpox
spreads through a population and what happens if inoculation is introduced.
Equipment
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Laboratory notebook
Pencil
Sheets of ¼ inch round stickers
Procedure
In this activity the spread of a virus will be modeled by the application of stickers.
For the simulation to work, everyone must follow certain ground rules:
 In each round, move slowly, quietly, and calmly around the room.
 If someone puts a sticker on your arm or hand, make sure it stays in place.
 Don’t actively avoid or seek out the virus carrier.
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PLTW Gateway – Medical Detectives Activity 8.1.3 Chickenpox Outbreak – Page 1
1. Follow your teacher’s instructions to complete Round 1 which simulates one virus
carrier infecting people with chickenpox.
2. Record the total number of infected individuals after Round 1: ___________
3. Remove all stickers and follow your teacher’s instructions to complete Round 2,
which simulates multiple chickenpox virus carriers infecting people.
4. Record the total number of infected individuals after Round 2: ___________
5. Answer conclusion questions 1-2 and remove all stickers.
6. In Round 3, 40% of the class will receive a vaccine against the chickenpox virus
which usually prevents the chickenpox disease completely or makes the illness
very mild. These students will have a different colored sticker on their hand.
Repeat Round 2 with multiple carriers.
7. Record the total number of infected individuals after Round 3: ___________
Note: Do not count individuals who were inoculated before the simulation began.
8. Answer conclusion question 3 and remove all stickers.
9. In Round 4, 80% of the class will receive a vaccine against the chickenpox virus.
Repeat the activity with multiple carriers.
10. Record the total number of infected individuals after Round 4: ___________
Note: Do not count individuals who were inoculated before the simulation began.
11. Remove all stickers and answer the remaining conclusion questions.
Conclusion
1. What were some differences between Round 1 and Round 2?
2. Does Round 1 or 2 more closely simulate the spread of an epidemic?
3. How does Round 3 compare with Round 2?
4. How does Round 4 compare with Rounds 2 and 3?
5. The chickenpox vaccine is known to be 99% effective at preventing the VZV
infection in children. With this in mind, how many of the students in Round 4
would have developed chickenpox?
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PLTW Gateway – Medical Detectives Activity 8.1.3 Chickenpox Outbreak – Page 2
6. How can a virus spread through a population?
7. Your school has a sudden, early outbreak of the flu. How can you protect
yourself from contracting this viral disease?
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PLTW Gateway – Medical Detectives Activity 8.1.3 Chickenpox Outbreak – Page 3