SIMULATING AN EPIDEMIC OF AN INFECTIOUS DISEASE

Epidemiologists study the causes and the spread of diseases through

populations. By doing this, they can help to control and prevent

diseases. Though epidemiologists may study diseases not caused by

microbes, the simulation you will be doing is a simple model of a

viral epidemic.

 

You will be simulating the spread of a viral disease by using

water and a chemical whose presence in the water can be easily shown.

 

Procedure:

 

A. Obtain a covered test tube of water from the supply area. All the

test tubes for the class have water in them. One of them appears

to be water but there is a chemical dissolved in it.

 

B. Go around the room and exchange liquids from your test tube with

three other people. To do this, pour one-half the volume of

liquid in your test tube into the test tube of a classmate. Then

that person should pour the same amount of liquid back into your

test tube. These actions represent the transfer of microbes

between persons.

 

C. Record the names of the persons with whom you interchange liquid

in the order in which you made the exchanges.

 

D. After you are finished with the exchanges, go to the instructor

who will add a chemical to the liquid in your tube. If the liquid

remains clear, then you are not infected. If a white cloudiness

appears in the liquid, then you are infected.

 

E. The problem the class must solve now is the identity of the person

who started the infection. It will be like solving a puzzle. You

will have to use the lists of contacts to see where each person

might have picked up the infection and work backwards until you

have determined who the original reservoir of infection. This is

much like the process that the epidemiologist uses to trace the

outbreak of a disease.

 

F. When you have finished your work, write a report which answers the

discussion questions.

 

Discussion Questions:

 

1. Did you find the source of the infection? If so, who was it?

 

2. Describe briefly the process you used to trace the infection back

to its source.

 

3. Was the epidemic a common-source epidemic or was it a propagated

epidemic? Explain.

 

4. In this simulation, what represented the infectious agent?

 

5. What is the morbidity rate for the infection in this simulation?

How did you calculate it?

 

 

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