Name: ________________________________ Date: __________________ Lab # ____________

Lab: The Spread of Disease

Part I:

Introduction: An infectious disease is any disease caused by germs that can be spread from one person to another. Germs include viruses, bacteria and protozoa. What are some infectious diseases? ____________________________________________________________________________________________________________________________________________________________ ______________________________________________________________________________ This activity will simulate the spread of an infectious disease. This simulation will show how an infectious disease can spread from one infected person to other people, who in turn infect others. You will be provided with the tools and a protocol to perform the simulation. You will be given a “body fluid” sample that you will share with your classmates. One or two of the samples in the class have been “infected.” You will also be provided with positive and negative control samples. Then you and your fellow students will test your samples for the presence of the “disease agent” to track the spread of the disease through your class population. Scenario:

The class has been on a field trip to the Natural History Museum in New York, NY. While on the Metro North train into the city, it is possible that you have been exposed to smallpox, deliberately released in aerosol form. Smallpox virus, if not exposed to UV light, may survive for >24 hours in cool, dry locations. It is important to determine as soon as possible which students have been exposed. Vaccination within 2-3 days of exposure can prevent smallpox, but the vaccine is in short supply. Vaccination of exposed individuals is essential to prevent further spread of the disease.

To determine which students have been exposed, perform an experiment to detect the virus samples in their body fluid. Students who test positive for the virus should undergo immediate vaccination.

Disease:

Name of pathogen Variola major, smallpox virus

Type of organism DNA virus in genus Orthopoxvirus

Infectious agent Virus (only a few virus particles needed for infection)

Method of spread Person to person via aerosols from infected individual. Can also be spread through infected clothing, bedding, etc.

Incubation 12-14 days

Symptoms High fever, headache, backache, abdominal pain, rash

Infectivity Most infectious at onset of rash; contagious until rash is totally gone.

Diagnosis Initially by symptoms. Virus identification by electron microscopy. Identification of viral DNA by molecular biological methods.

Treatment Post exposure vaccination with 2-3 days of exposure protects against the disease. Post exposure vaccination with 4-5 days of exposure may prevent a fatal outcome. After 4-5 days post exposure, supportive treatment only. Experimental treatment with antiviral drugs.

Mortality Up to 30%

History as a pathogen

Used for biological warfare by British in North America in the 18th century. Army distributed blankets that had been used by smallpox patients. Mortality in some Native American tribes was 50%. In 1796, Jenner discovered cowpox vaccine effective against smallpox. Global immunization effort eradicated smallpox in 1977, and routine vaccination creased. May have been weaponized in the Soviet Union in the 1980s

Materials:

Disposable 2 oz. or medicine cups with “body fluid”

Goggles

Plastic droppers or glass pipettes with squeezable tops

pH indicator: phenolphthalein (C20H14O4), which turns alkaline solutions pink.

Procedure:

Step 1: Make observations on the liquid in your cup and record them below:

a. Color of the liquid: ________________

b. Smell of the liquid: ________________

Step 2: Record your cup number in column B of the Exchange Data Table below.

Step 3: Exchange the liquid in your cup with that of another student. First, record his or her cup number in column B of the Table below, and then pour the liquid from one cup into the other student’s cup.

Next divide the mixture evenly into the two cups. Repeat this with two other students, so you have had a total of three exchanges.

Step 4: After competing three exchanges, record the color and smell of your liquid below:

c. Color of the liquid: ______________

d. Smell of the liquid: ______________

Step 5: After three exchanges, have teacher add phenolphthalein solution to your cup and record the color of the liquid in your cup in column C in the Exchange Table. Also, record in column C the color of the liquid in each of the three cups that you have exchanged liquids in Step 2.

Exchange Data Table

A B (Step 2) Record each cup number

C (Step 5) Record the color of the

liquid after teacher adds the solution to each cup

Your cup

1st exchange

2nd exchange

3rd exchange

Instructions: Complete this “tree” to trace back the path of transmission of the disease. Write your and the names of the three partners that you exchanged fluids with. Find out which of your partners had a positive test (were infected). Highlight their names. Talk to each of your partners and find out if they had interactions with infected people before they interacted with you. Circle the name of the partner that infected you. Draw a box around the names of the people that you infected (directly or indirectly)

PART II: Log onto the website http://www.pbs.org/wgbh/nova/bioterror/vaccines.html

In your own virtual laboratory, you will use different techniques to create six different vaccines.

To make a vaccine, first select one of the six pathogens listed. Follow the step by step instructions. Choose at least two pathogens and list the steps in the following chart.

Name of pathogen: ____________________________________________

Steps used to create vaccine

1.

2.

3.

4.

5.

6.

Name of pathogen: ____________________________________________

Steps used to create vaccine

1.

2.

3.

4.

5.

6.

Part III: Investigations into Specific Diseases

1. Read the article “Achievements in Public Health” found on the Center for Disease Control website http://www.cdc.gov/mmwr/preview/mmwrhtml/00056803.htm

2. Select one disease that is vaccine preventable from Table 2 (excluding smallpox). Conduct research on that disease to complete the disease table. Type your disease in the search box for link to CDC page.

Disease name: _________________________________________________

Name of pathogen

Type of organism

Infectious agent

Method of spread

Incubation

Symptoms

Infectivity

Diagnosis

Treatment

Mortality

History as a pathogen

Part IV: Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with certain health conditions are at high risk for serious flu complications. The best way to prevent the flu is by getting vaccinated each year.

Directions: Using the vaccination coverage data table, construct a line graph for 10 years of data. ***You may choose the age group and category just make sure to title it correctly. http://www.cdc.gov/flu/pdf/professionals/nhis89_08fluvaxtrendtab.pdf

Title: _________________________________