"Let's take a look at the kids and find out," he said as he led them behind curtain three. "Don't

jump to conclusions."

Two hours and many patients later, Frank, Sam, and Ami von Hoffer, the epidemiologist, sat together poring over the information they had gathered . Ami pulled out a marker and started

charting on the board.

"Okay, we have 28 patients admitted, all under age 10. Their parents and any older siblings have some intestinal distress, but mild compared to the admissions. What else do we know?" She

looked over at the two men as they scanned the charts.

"The children are all showing symptoms of some kind of hemolytic anemia . There are bruises and small hemorrhages visible in the mucosa! lining of the mouth. RBC, hemoglobin, and platelet counts are all way down." Sam just shook his head . "Poor kids. Looks like the intestinal lining is

being attacked by something. Food poisoning?"

"The youngest are beginning to show signs of kidney failure. Is that typical?" asked Frank.

"Have the lab cultures turned up anything yet?" Ami asked just as a tech pushed open a door, a

sheath of papers clutched in her hand.

"Here are the prelims," she said. " No major parasites, a few pinworms, but that's not unusual. Did find positives for 026:Hll. Looks like you have an enterohemorrhagic E. coli. Same strain as the

beef outbreak up north last month. Have fun ."

"Great, food poisoning. Now I have to track down the source." Ami pulled out the laptop and opened a file . "Looks like a long day. Can you start sending in the parents who are out there?"

Questions -Answer the following questions based on what you know or what Google has to tell you.

1. What is the most common source of contamination with f . coli?

2. At this point, can you make some preliminary guesses as to the source of the infection?

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3. What information should Ami gather from the victims and their families?

4. Why do children seem to be the most ill?

5. How does this bacterium damage its victims?

Part II-Clean Kitchen?

Two days later, Ami knocked on the door of a neat house in the neighborhood of the sick children. The one thing all the victims had in common was strawberry pie. Miss Emma Braithwaite, well into her eighties, had promised the neighborhood children fresh strawberry pie in exchange for them picking berries from her backyard. Miss Emma's pies were well loved by everyone. So, the children had picked berries, and Miss Emma had made over a dozen pies to share. Unfortunately, a pinch of

E. coli seems to have been added to the usual ingredients.

The door was opened by a small woman with snowy hair and snapping eyes. "May I help you, miss?"

she asked.

"Yes, ma'am. I am looking for Miss Braithwaite . I am Dr. Ami van Hoffer. I'm with the county."

"Come in, come in. I heard you've been talking with the neighbors about the sick children. Have you

found out the problem?" Miss Emma held the door open .

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Ami entered the spotless house. This was the part of her job she really disliked. "That's what I've b

. h d nastY toxin . It come to talk to you about. We've tracked the illness to a acterium t at pro uces a

causes a type of food poisoning."

"I don't know anything about food poisoning," Miss Emma remarked as she offered Ami a chai~- ,, "Only food . I used to be a cook. May I offer you a bite to eat? I was just about to have some pie.

Ami schooled her features. "You haven't eaten any of the pie yet, have you?" she asked .

"Child, I can hear it in your voice . What are you not telling me?" Miss Emma sat rigidly down in

a straight- backed chair near the window .

"Ma'am, we think the bacteria came from the strawberry pies you made. It is the only thing everyone ate. Please tell me you haven't eaten any. If you still have some, I need to sample it."

Miss Emma sat even straighter. "I keep a clean kitchen. Different knives between raw meat and fresh produce. Wipe down the cutting board between foods. I pay attention, so don't you try to

tell me I poisoned someone."

"Ma'am, we didn't say you poisoned anyone, but we are concerned the berries may have been contaminated. Please, you haven't eaten any, have you? No offense, but at your age food

poisoning could be very serious."

"Bah, I keep a clean kitchen. I washed all the berries well." Miss Emma got slowly up from her

chair. "Come see my kitchen ."

"There was an outbreak of this same strain up north last month. It came from hamburger. Have you had any hamburger lately?" Ami followed her into the kitchen. Like the rest of the house, it was spotless and smelled faintly of some cleaner. The aroma brought back memories of her grandmother's

house.

Miss Emma stopped short. "I had some hamburger that thawed in the refrigerator. It leaked all over. I threw it out because I didn't trust it. Made a right mess in the kitchen . Scrubbed it all down before I made the pies. Same cleaner I've been using for years. No one ever got sick before. Go right ahead and run your little swabs along the counter. Right there is where I made the pies."

Questions – Answer the following questions based on what you know.

1. Based on this additional information, how do you think the pies became contaminated?

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. h from the samples that 2. What would you expect from the cultures (the microbes t at gro~

were collected from swabbing different surfaces) of the counter •

3. What other objects would you culture in the kitchen? Why?

4 . What would you expect to find from the kitchen samples?

5 . Miss Emma cleans well. How is it that some E. coli survived (think about antibiotics and the problem with using them too often)?

6. What could be changed to prevent this from happening again?

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Before you begin this activity, please read the following information and respond to the questions. If you answer yes to any of these questions, see if you can recruit someone else to be the runner .

Yes No

' 1. Has your doctor ever said that you have a heart condition and that you should only do D l!:J"' physical activity recommended by a doctor?

D E:( 2. Do you feel pain in your chest when you do physical activity?

cef 3. In the past month, have you had chest pain when you were not doing physical activity?

D a 4. Do you lose your balance because of dizziness or do you ever lose consciousness? Q"'

5. Do you have a bone or joint problem that could be made worse by a change in your physical activity?

D CY · 6. Is your doctor currently prescribing drugs (for example, water pills) for your blood pressure or heart condition? /

D cv 7. Do you know of any other reason why you should not do physical activity?

To make sure everyone is collecting data in the same manner, please use the following procedures for measuring heart rate and respiratory rate.

How to determine your heart and respiratory rates:

Radial pulse Using your index and middle fingers, apply gentle pressure at the radial (wrist) artery, located just below the base of the thumb.

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Carotid pulse Place the index and middle fingers of your right hand on your Adam's apple. Slide your fingers to the right approximately one inch and you should feel a pulse when applying gentle pressure with the tips of

your fingers. Note: Do not apply too much pressure on the carotid artery as this may cause a "reflex" which could

slow the heart rate. ) y

JJ. To obtain your heart rate, count th~ ber of beats during a ten-second period and then multiply by

sixforaone-minutecoJnt. 7~ b/ ""? To obtain your respiratory rate, have someone else count the number of breaths you take during the same ten-second period you are monitoring your heart rate and then multiply by six for a one minute

count. 30 Example: 24 beats or breaths in 10 seconds (x6) equals 144 beats/minute.

The activity will consist of walking up and down the stairs (or another form of activity that will raise your heart rate) for a specific amount of time and measuring heart rate and respiratory rate. You will record your results in a table and then look for patterns and trends. You will then try to explain what you measure. You can do this activity on your own, but you can also ask for help from people in your household. All work that is submitted must be your own work. Indicate if you had help to do

the activities.

f

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Observation: When I run up the stairs to lab I get out of breath and my heart seems to race . When I get to lab and sit down for a minute or two, my breathing returns to normal and my heart slows down .

Question:

Hypothesis:

Experiment:

1. Get set up with a stopwatch and your data sheets. 2. Get set up in a stair well, or wherever you are doing your activity. Practice measuring heart rate

and respiratory rate . 3. Trial 1

a. Measure the official resting heart rate and respiratory rate. If you are doing this on your own, record the same rate, either heart or respiratory, each time. For example, if you measure respiratory rate first in this step, measure respiratory rate first each time.

b. Record the resting heart rate and resting respiratory rate in the table for Trial 1. Record in beats or breaths per minute.

c. Walk up and down the stairs at a moderate pace for 2 minutes. d. At the end of 2 minutes, measure heart rate and respiratory rate. e. Record the heart rate and respiratory rate in the table for Trial 1. f. Monitor the heart rate and respiratory rate every 30 seconds until they return to the

resting rates. They may not be exactly what the resting rates were, but they should be very close. Record how long it takes for the heart rate to return to resting rates.

4. Trial 2 a. Walk up and down the stairs at a moderate pace for 2 minutes, as in Trial 1.

b. At the end of 2 minutes, measure heart rate and respiratory rate. c. Record the heart rate and respiratory rate in the table for Trial 2. Record in beats or

breaths per minute. d. Monitor the heart rate and respiratory rate every 30 seconds until they return to the

resting rates. They may not be exactly what the resting rates were, but they should be very close. Record how long it takes for the heart rate to return to resting rates.

5. Trial 3 a. Walk up and down the stairs at a moderate pace for 2 minutes, as in Trial 1.

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Results:

Trial 1

Trial 2

Trial 3

"' b. At the end of 2 minutes, measure heart rate and respiratory rate. c. Record the heart rate and respiratory rate In the table for Trial 3. Record in beats or

breaths per minute( d. Monitor the heart rate and respiratory rate every 30 seconds until they return to the

rest ingWes . They may not be exactly what the resting rates were, but they should be very-close. Record how long it takes for the heart rate to return to resting rates.

Resting After Exercise.–

, ~ art Rate Respiratory Heart Rate· Respiratory

Recovery Time

Rate Rate

–7 <y ( 30 Y O ½~ )>

7 2- 30 j Y O 5~ 3oµc

12 3b I 20 to 35 /JL· Observations. Answer the questions to help think about the results and the experiment.

1. Did the heart rate and respiratory rate increase after walking up and down the stairs? By

how much? Was this expected?

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2. Calculate the percent increase in heart rate and respiratory rate for each trial. To calculate the percent Increase, divide the difference between resting and after exercise by the resting rate .

il. Afte r – resting= difference b. (Difference divided by resting) • 100 = % increase 1

Heart Rate Resti ng

Trial 1

Trial 2

Trial 3 7 2-Respiratory Rate

Resti ng

Trial 1

Trial 2 3o

Trial 3

After Stairs

/2–0

I 2. O

After Stairs

Difference

Difference

)2

2–Y I

1 i–! L- i

% Increase

35

40 40

% Increase

37 5

SSI Page

.6

3. Did the percent increase change over the three trials? Describe the change. For example, did th

e percent Increase get smaller or bigger over the three trials? Remembe r that the percent increase represents how much higher the heart and respiratory rates were after the exercise.

4. Explain any changes you saw or did not see.

5. Did the recovery time change from trial to trial? Describe the change .

6. Exp lain an y changes you saw or did not see. Use the background information in this document to help you explain the chan ge s.

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7. Why do different people have different res ting hea rt and respiratory ra tes, different increases in hea rt and res piratory rates aft er exercise, and dlfforcnt recove ry times? You can use the background lnfom,a tlon In thi s docum ent and anyt hing else you know about these body sy1 tem s.

8. What was tested here and what was not controlled for by this experimental design?

Conclusion:

Restate your hypothesis and indicate if it was supported. If your hypothesis was not supported, can you explain why it was not supported?

Next question or observation:

What would you do next?

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