1

Score:_________

Rank:__________

Team Number: __________

School Name: _____________________________________________________

Student Names: ____________________________________________________

Disease Detectives – C

UW Milwaukee Regional Event

January 28th, 2017

2

Please read all questions carefully.

Please mark your answers on the test.

Please write clearly.

1. Match the following terms to their definitions in the table on the following page by writing the

corresponding letter into the column marked ‘Term’. Note that not all terms will be used and

that there is only one correct answer per definition. (16 points)

A. Active Immunity

B. Age adjusted mortality rate

C. Age specific mortality rate

D. Association

E. Case definition

F. Case-control Study

G. Cohort Study

H. Confounding

I. Droplet spread transmission

J. Epidemiology

K. Etiology

L. Fomite

M. Incidence

N. Infectivity

O. Interval Scale

P. Morbidity

Q. Passive Immunity

R. Pathogenicity

S. Point Source

T. Prevalence

U. Propagated Source

V. Prospective study

W. Ratio Scale

X. Vector borne transmission

Y. Vehicle borne transmission

Z. Virulence

3

Term Definition

a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute.

an analytic study in which participants are enrolled before the health outcome of interest has occurred

transmission of an agent by an inanimate object; considered a type of indirect transmission; includes foodborne and waterborne transmission

measure of the degree of disease that a pathogen causes

a measurement scale consisting of quantitative categories whose values are measured on a scale of equally spaced units, but without a true zero point (e.g., date of birth)

a common source outbreak in which the exposure period is relatively brief so that all cases occur within one incubation period

the rate of new cases of illness commencing during a specified time period in a given population

immunity conferred by an antibody produced in another host This type of immunity can be acquired naturally by an infant from its mother or artificially by administration of an antibody-containing preparation (e.g., antiserum or immune globulin)

the distortion of the association between an exposure and a health outcome by a third variable that is related to both

the study of the cause or origin of a disease

a mortality rate that has been statistically modified to eliminate the effect of different age distributions among different populations

an inanimate object that can be the vehicle for transmission of an infectious agent (e.g., bedding, towels, or surgical instruments)

uniform set of criteria that specifies clinical information, details of time, place, and person and is used to determine if an individual is part of an outbreak

the direct transmission of an infectious agent by means of the aerosols produced in sneezing, coughing, or talking that travel only a short distance before falling to the ground

any departure, subjective or objective, from a state of physiological or psychological health and well-being

the study of the distribution and determinants of health conditions or events among populations and the application of that study to control health problems

4

2. Fill in all the blanks in the table. Row 1 is already done. (10 points)

Scientific Name of pathogen

Type of pathogen

Food borne disease caused by pathogen

Transmission/Food Source

Clostridium botulinum

Bacteria Botulism vegetables, canned food

Yersinia enterocolitica

Yersiniosis

perfringens food poisoning

meat poultry

Hepatitis A

Giardia

food, or water that has been contaminated with feces from infected humans or animals.

Toxoplasmosis

Cyclospora cayetanensis

fresh produce contaminted with feces

Shigella Bacteria

Salmonellosis eggs, poultry, dairy

Bacteria Hemorrhagic colitis

The following is modified information taken from “Leveling of Tuberculosis Incidence — United States,

2013–2015” MMWR Weekly / March 25, 2016 / 65(11);273–278:

“After 2 decades of annual declines, TB (Tuberculosis) incidence in the United States has leveled. The

determinants of this leveling in TB incidence are not yet clear; further evaluation of available data is

required to understand the causes of this trend. Health departments in the 50 states and District of

Columbia (DC) electronically report verified tuberculosis (TB) cases that meet the CDC and Council of

State and Territorial Epidemiologists case definition to the National Tuberculosis Surveillance System.”

3. What are the four parts of a case definition? (4 points)

a.

b.

c.

d.

4. What pathogen causes TB (a), how is this disease transmitted (b), and who is credited with its

discovery? (3 points) TIEBRAKER 1

a.

b.

c.

5

The authors of this study compiled some of the data into the following table for interpretation and some

statistical analysis:

TABLE 1. Tuberculosis (TB) case counts and incidence, by U.S. Census division and state — United States, 2014 and 2015

6

Use the data from the table to answer the following questions:

5. What is the TB incidence per 100,000 for the total US population in 2015? (2 points)

6. Calculate the total population in Kansas in 2015. Show your work. (3 points total) TIEBRAKER 2

7. In 2015, which state had the lowest incidence and what was it? (1 point)

8. In 2015, which state had the highest incidence and what was it? (1 point)

9. Based on your two previous answers, what would be more meaningful to calculate in order to

compare state incidence across the entire US, the mean or the median of all state incidence and

why? (3 points total)

10. Calculate the mean (a) and median (b) of reported TB cases for Division 4 for 2014. Show all

your work and round to three digits. (4 points total)

a.

b.

11. Which of the following would help to further decline the incidence of TB? Circle all that apply. (2

points)

a. Strengthen systems that aim to interrupt TB transmission.

b. Increase testing and treatment of people with latent TB infections.

c. Identify specific demographic populations most at risk.

d. Vaccinate populations most at risk.

7

The next set of data is taking from Emerging Infectious Diseases, Volume 19, Number 3—March 2013,

DOI: 10.3201/eid1903.111866:

“Attribution of Foodborne Illnesses, Hospitalizations, and Deaths to Food Commodities by using

Outbreak Data, United States, 1998–2008

Each year, >9 million foodborne illnesses are estimated to be caused by major pathogens

acquired in the United States. Preventing these illnesses is challenging because resources are

limited and linking individual illnesses to a particular food is rarely possible except during an

outbreak. The authors reviewed all outbreaks from 1998, the first year with detailed information

on ingredients, through 2008 that were reported to the CDC by October 2010. For this analysis,

they included all outbreaks with an implicated food vehicle and a single etiologic agent.”

12. Which of the following terms does not apply to vehicle transmission? Circle all that apply. (2

points)

a. Fomite

b. Cooking utensil

c. Indirect

d. Malaria

13. Which of the following is not an etiological agent that can cause a foodborne disease? Circle all

that apply. (2 points)

a. Rotavirus

b. Vibrio vulnificus

c. Trichinella spiralis

d. Yersinia Pestis

14. State and local health departments report foodborne disease outbreaks to the Center for

Disease Control and Prevention (CDC). The ongoing systematic collection and recording of such

data used for analysis, and interpretation is part of which of the following? Circle all that apply.

(2 points)

a. Cluster

b. Surveillance

c. Incidence

d. Prevalence

8

The authors compiled information on %hospitalization in the following table:

Table 2 Estimates of annual hospitalizations for domestically acquired foodborne illnesses attributed to specific food

commodities and commodity groups, by pathogen type, United States, 1998–2008

15. This table lists bacterial, chemical/toxins, parasitic, and viral agents. Which of the following are

characteristics of viruses? Circle all that apply. (2 points)

a. Can replicate outside of a living cell.

b. Can have RNA or DNA

c. Can infect plants.

d. Can be seen with a light microscope.

Commodity or commodity group No. (%) hospitalizations

All agents Bacterial Chemical/toxin Parasitic Viral

Aquatic animals† 3,199 (5.6) 1,158 (3.2) 921 (61.6) 231 (4.7) 889 (5.8)

Fish 1,661 (2.9) 210 (0.6) 894 (59.8) 6 (0.1) 551 (3.6)

Shellfish† 1,538 (2.7) 948 (2.6) 27 (1.8) 225 (4.6) 338 (2.2)

Crustaceans 117 (0.2) 75 (0.2) 7 (0.5) 34 (0.2)

Mollusks 1,421 (2.5) 873 (2.4) 20 (1.3) 225 (4.6) 303 (2.0)

Land animals† 26,118 (45.5) 21,471 (60.0) 198 (13.3) 6 (0.1) 4,443 (29.1)

Dairy 9,284 (16.2) 7,464 (20.9) 23 (1.5) 1,798 (11.8)

Eggs 4,062 (7.1) 2,979 (8.3) 42 (2.8) 1,041 (6.8)

Meat-poultry† 12,772 (22.2) 11,029 (30.8) 134 (8.9) 6 (0.1) 1,604 (10.5)

Meat† 6,138 (10.7) 5,238 (14.6) 15 (1.0) 6 (0.1) 880 (5.8)

Beef 3,075 (5.4) 2,650 (7.4) 4 (0.3) 421 (2.8)

Game 117 (0.2) 94 (0.3) 9 (0.6) 6 (0.1) 8 (0.1)

Pork 2,946 (5.1) 2,494 (7.0) 1 (0.1) 450 (2.9)

Poultry 6,634 (11.5) 5,791 (16.2) 119 (8.0) 724 (4.7)

Plants† 23,506 (40.9) 13,043 (36.4) 377 (25.2) 221 (4.5) 9,865 (64.5)

Grains-beans 1,437 (2.5) 695 (1.9) 78 (5.2) 664 (4.3)

Oils-sugars 184 (0.3) 14 (0.9) 170 (1.1)

Produce† 21,885 (38.1) 12,349 (34.5) 284 (19.0) 221 (4.5) 9,031 (59.1)

Fruits-nuts 5,829 (10.1) 3,279 (9.2) 177 (11.8) 213 (4.4) 2,160 (14.1)

Vegetables† 16,057 (27.9) 9,070 (25.3) 108 (7.2) 8 (0.2) 6,871 (45.0)

Fungi 37 (0.1) 14 (0.0) 23 (1.5)

Leafy 7,769 (13.5) 2,393 (6.7) 55 (3.7) 7 (0.1) 5,314 (34.8)

Root 1,501 (2.6) 793 (2.2) 7 (0.5) 700 (4.6)

Sprout 713 (1.2) 713 (2.0)

Vine-stalk 6,038 (10.5) 5,157 (14.4) 22 (1.5) 1 (0.0) 857 (5.6)

Undetermined 4,639 (8.1) 124 (0.3) 4,428 (90.6) 87 (0.6)

Total 57,462 (100.0) 35,797 (100.0) 1,496 (100.0) 4,886 (100.0) 15,284 (100.0)

9

16. Which of the following does not apply to parasitic protists? Circle all that apply. (2 points)

a. Has RNA and DNA

b. Are not animal, plant, or fungus

c. Require a host for reproduction

d. Diseases they cause can be treated with antibiotic

17. According to the table, which of the following are commodity groups? Circle all that apply. (2

points)

a. Plants

d. Beef

e. Aquatic Animals

f. Shellfish

18. Which single commodity (i.e. not group) listed in the table caused the most hospitalization?

(2 points)

19. For the Leafy commodity listed in the table which agent caused the most hospitalization (a) and

which specific organism was the most likely the highest contributor to that agent (b)? (3 points)

a.

b.

20. For the Fish commodity, chemical/toxin agents caused the most hospitalization. Name a type of

food borne disease caused by chemical/toxins when eating fish (a), symptoms associated with

the disease (b), and the cause of the toxins (c). (3 points) TIEBREAKER 3

a.

b.

c.

10

On March, 10th, 2014 the Wisconsin Department of Health was informed of an outbreak of gastro-intestinal illness in the pediatric ward of the hospital in Milwaukee. 25 people, 15 patients and 10 staff members from the pediatric ward had reportedly fallen ill since February 19th. Symptoms included cramps, diarreah, and vomiting. Laboratory testing of stool samples of the affected individuals showed the presence of Campylobacter jejuni, which has an incubation time of 2-5 days. The health department immediately started an investigation. The investigators defined a case as a patient or member of staff of the pediatric ward who developed diarrhea, cramps, vomiting and tested positive for Campylobacter jejuni between February 19th and March 10th 2014. The investigators suspected a single food source to be the culprit.

21. Why do you think the health department decided to investigate the outbreak? Circle all that apply. (2 points) a. Identify the source and eliminate it b. Develop strategies to prevent further outbreaks c. Evaluate existing preventative measures d. All of the above

22. What is the term for a disease occurring or acquired in a hospital setting? (1 points)

23. In order the classify a case associated with this outbreak as possible, probable, or confirmed, investigators most likely organized data into what type of table? (1 points)

The following data was collected:

Date of onset

19-Feb 20-Feb 21-Feb 22-Feb 23-Feb

Number of cases

3 7 10 4 1

24. Draw an epicurve using the above table. Use the empty space on the next page. Make sure to include every necessary information on the graph. Please note that no other cases were reported prior to 19-Feb and after 23-Feb. (8 points)

11

Draw Epi curve here:

25. What type of outbreak does your epi curve indicate (a)? Does this support the suspicion of a single food source as the culprit (b)? Explain your answer. (2 points) a.

b.

26. The investigators are suspecting that all affected individuals consumed the contaminated food

on the same date. On what date was the contaminated food most likely consumed? Explain your answer. (3 points)

One common source of Campylobacter jejuni food poisoning is raw or undercooked chicken. The investigators decided to conduct a study to determine if chicken that was served at the pediatric ward the days preceding the outbreak was the culprit. The investigators were able to gather information about all patients and staff in terms of whether they had eaten the chicken or not. They decided to compare confirmed cases who ate chicken with patients and staff who also ate the chicken but did not become ill. Of the 25 confirmed cases, 23 reported to have eaten chicken. Of the patients and staff who did not become ill, 42 reported to have eaten the chicken. There were a total of 90 patients and staff in the pediatric ward during the days preceding the outbreak.

27. What type of study is this? Circle all that apply. (2 points) a. Cross-sectional b. Experimental c. Observational d. Case-control

12

28. Arrange the information from the above paragraph into a meaningful 2X2 table. (4 points)

29. What can you calculate from the table (a)? Perform the calculation (b), and interpret the result (c). (5 points) a.

b.

c.

30. How do you explain the two confirmed cases that did not eat the chicken? (3 points)

THE END

1

Score:_________

Rank:__________

Team Number: __________

School Name: _____________________________________________________

Student Names: ____________________________________________________

Disease Detectives – C

UW Milwaukee Regional Event

January 28th, 2017

2

Please read all questions carefully.

Please mark your answers on the test.

Please write clearly.

1. Match the following terms to their definitions in the table on the following page by writing the

corresponding letter into the column marked ‘Term’. Note that not all terms will be used and

that there is only one correct answer per definition. (16 points)

A. Active Immunity

B. Age adjusted mortality rate

C. Age specific mortality rate

D. Association

E. Case definition

F. Case-control Study

G. Cohort Study

H. Confounding

I. Droplet spread transmission

J. Epidemiology

K. Etiology

L. Fomite

M. Incidence

N. Infectivity

O. Interval Scale

P. Morbidity

Q. Passive Immunity

R. Pathogenicity

S. Point Source

T. Prevalence

U. Propagated Source

V. Prospective study

W. Ratio Scale

X. Vector borne transmission

Y. Vehicle borne transmission

Z. Virulence

3

Term Definition

F a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute.

V an analytic study in which participants are enrolled before the health outcome of interest has occurred

Y transmission of an agent by an inanimate object; considered a type of indirect transmission; includes foodborne and waterborne transmission

Z measure of the degree of disease that a pathogen causes

O a measurement scale consisting of quantitative categories whose values are measured on a scale of equally spaced units, but without a true zero point (e.g., date of birth)

S a common source outbreak in which the exposure period is relatively brief so that all cases occur within one incubation period

M the rate of new cases of illness commencing during a specified time period in a given population

Q immunity conferred by an antibody produced in another host This type of immunity can be acquired naturally by an infant from its mother or artificially by administration of an antibody-containing preparation (e.g., antiserum or immune globulin)

H the distortion of the association between an exposure and a health outcome by a third variable that is related to both

K the study of the cause or origin of a disease

B a mortality rate that has been statistically modified to eliminate the effect of different age distributions among different populations

L an inanimate object that can be the vehicle for transmission of an infectious agent (e.g., bedding, towels, or surgical instruments)

E uniform set of criteria that specifies clinical information, details of time, place, and person and is used to determine if an individual is part of an outbreak

I the direct transmission of an infectious agent by means of the aerosols produced in sneezing, coughing, or talking that travel only a short distance before falling to the ground

P any departure, subjective or objective, from a state of physiological or psychological health and well-being

J the study of the distribution and determinants of health conditions or events among populations and the application of that study to control health problems

2. Fill in all the blanks in the table. Row 1 is already done. (10 points)

4

Scientific Name of pathogen

Type of pathogen

Food borne disease caused by pathogen

Transmission/Food Source

Clostridium botulinum

Bacteria Botulism vegetables, canned food

Yersinia enterocolitica

Bacteria Yersiniosis Raw or undercooked pork

Clostridium perfringen

Bacteria perfringens food poisoning

meat poultry

Hepatitus A virus

Virus Hepatitis A Contaminated food, water, person-to-person, fish from contaminated water

Giardia Parasite Giardiasis food, or water that has been contaminated with feces from infected humans or animals.

Toxoplasma gondii

Parasite Toxoplasmosis Undercooked contaminated meat, water

Cyclospora cayetanensis

Parasite Cyclosporiasis fresh produce contaminted with feces

Shigella Bacteria Shigellosis Food contaminated with feces

Samonella Bacteria Salmonellosis eggs, poultry, dairy

E. coli O157:H7 Bacteria Hemorrhagic colitis

Undercooked beef, unpasteurized milk, raw fruit, sprouts, contaminated water

The following is modified information taken from “Leveling of Tuberculosis Incidence — United States,

2013–2015” MMWR Weekly / March 25, 2016 / 65(11);273–278:

“After 2 decades of annual declines, TB (Tuberculosis) incidence in the United States has leveled. The

determinants of this leveling in TB incidence are not yet clear; further evaluation of available data is

required to understand the causes of this trend. Health departments in the 50 states and District of

Columbia (DC) electronically report verified tuberculosis (TB) cases that meet the CDC and Council of

State and Territorial Epidemiologists case definition to the National Tuberculosis Surveillance System.”

3. What are the four parts of a case definition? (4 points)

a. time --- 1 point

b. place --- 1 point

c. person --- 1 point

d. clinical features/laboratory confirmed (take either or both answers) --- 1 point

4. What pathogen causes TB (a), how is this disease transmitted (b), and who is credited with its

discovery? (3 points) TIEBRAKER 1

a. Mycobacterium tuberculosis --- 1 point

b. Aerosol (or airborne) --- 1 point

c. Robert Koch --- 1 point

5

The authors of this study compiled some of the data into the following table for interpretation and some

statistical analysis:

TABLE 1. Tuberculosis (TB) case counts and incidence, by U.S. Census division and state — United States, 2014 and 2015

6

Use the data from the table to answer the following questions:

5. What is the TB incidence per 100,000 for the total US population in 2015? (2 points)

3.0

6. Calculate the total population in Kansas in 2015. Show your work. (3 points total) TIEBRAKER 2

Use formula for incidence rate per 100,000. # of new cases/total population at risk * 100,000 =

incidence rate; thus 36/x * 100,000 = 1.2 where x is total population; x = 3,000,000

7. In 2015, which state had the lowest incidence and what was it? (1 point)

West Virgina, 0.5

8. IN 2015, which state had the highest incident and what was it? (1 point)

Alaska, 9.1

9. Based on your two previous answers, what would be more meaningful to calculate in order to

compare state incidence across the entire US, the mean or the median of all state incidence and

why? (3 points total)

Median as data is skewed (outliers, wide range) --- 1 point for correct answer, 2 points for

correct explanation

10. Calculate the mean (a) and media (b) of reported TB cases for Division 4 for 2014? Show all your

work and round to three digits. (4 points total)

a. 54.6 --- 2 points

b. Arrange number of reports from smallest to largest: ---- 2 points

8

15

38

40

54

80

147 Since there is an odd number of reported cases (7), add one to give you 8, then divide by

2, which will give you 4 and is the position in the list that is the median.

7

11. Which of the following would be appropriate choices to help further decline the incidence of

TB? Circle all that apply. (2 points)

a. Strengthen systems that aim to interrupt TB transmission.

b. Increase testing and treatment of people with latent TB infections.

c. Identify specific demographic populations most at risk.

d. Vaccinate populations most at risk.

The next set of data is taking from Emerging Infectious Diseases, Volume 19, Number 3—March 2013,

DOI: 10.3201/eid1903.111866:

“Attribution of Foodborne Illnesses, Hospitalizations, and Deaths to Food Commodities by using

Outbreak Data, United States, 1998–2008

Each year, >9 million foodborne illnesses are estimated to be caused by major pathogens

acquired in the United States. Preventing these illnesses is challenging because resources are

limited and linking individual illnesses to a particular food is rarely possible except during an

outbreak. The authors reviewed all outbreaks from 1998, the first year with detailed information

on ingredients, through 2008 that were reported to the CDC by October 2010. For this analysis,

they included all outbreaks with an implicated food vehicle and a single etiologic agent.”

12. Which of the following terms does not apply to vehicle transmission? Circle all that apply. (2

points)

a. Fomite

b. Cooking utensil

c. Indirect

d. Malaria

13. Which of the following is not an etiological agent that can cause a foodborne disease? Circle all

that apply. (2 points)

a. Rotavirus

b. Vibrio vulnificus

c. Trichinella spiralis

d. Yersinia Pestis

14. State and local health departments report foodborne disease outbreaks to the Center for

Disease Control and Prevention (CDC). The ongoing systematic collection and recording of such

data used for analysis, and interpretation is part of which of the following? Circle all that apply.

(2 points)

a. Cluster

b. Surveillance

c. Incidence

d. Prevalence

8

The authors compiled information on %hospitalization in the following table:

Table 2 Estimates of annual hospitalizations for domestically acquired foodborne illnesses attributed to specific food

commodities and commodity groups, by pathogen type, United States, 1998–2008

15. This table lists bacterial, chemical/toxins, parasitic, and viral agents. Which of the following are

characteristics of viruses? Circle all that apply. (2 points)

a. Can replicate outside of a living cell.

b. Can have RNA or DNA

c. Can infect plants.

d. Can be seen with a light microscope.

Commodity or commodity group No. (%) hospitalizations

All agents Bacterial Chemical/toxin Parasitic Viral

Aquatic animals† 3,199 (5.6) 1,158 (3.2) 921 (61.6) 231 (4.7) 889 (5.8)

Fish 1,661 (2.9) 210 (0.6) 894 (59.8) 6 (0.1) 551 (3.6)

Shellfish† 1,538 (2.7) 948 (2.6) 27 (1.8) 225 (4.6) 338 (2.2)

Crustaceans 117 (0.2) 75 (0.2) 7 (0.5) 34 (0.2)

Mollusks 1,421 (2.5) 873 (2.4) 20 (1.3) 225 (4.6) 303 (2.0)

Land animals† 26,118 (45.5) 21,471 (60.0) 198 (13.3) 6 (0.1) 4,443 (29.1)

Dairy 9,284 (16.2) 7,464 (20.9) 23 (1.5) 1,798 (11.8)

Eggs 4,062 (7.1) 2,979 (8.3) 42 (2.8) 1,041 (6.8)

Meat-poultry† 12,772 (22.2) 11,029 (30.8) 134 (8.9) 6 (0.1) 1,604 (10.5)

Meat† 6,138 (10.7) 5,238 (14.6) 15 (1.0) 6 (0.1) 880 (5.8)

Beef 3,075 (5.4) 2,650 (7.4) 4 (0.3) 421 (2.8)

Game 117 (0.2) 94 (0.3) 9 (0.6) 6 (0.1) 8 (0.1)

Pork 2,946 (5.1) 2,494 (7.0) 1 (0.1) 450 (2.9)

Poultry 6,634 (11.5) 5,791 (16.2) 119 (8.0) 724 (4.7)

Plants† 23,506 (40.9) 13,043 (36.4) 377 (25.2) 221 (4.5) 9,865 (64.5)

Grains-beans 1,437 (2.5) 695 (1.9) 78 (5.2) 664 (4.3)

Oils-sugars 184 (0.3) 14 (0.9) 170 (1.1)

Produce† 21,885 (38.1) 12,349 (34.5) 284 (19.0) 221 (4.5) 9,031 (59.1)

Fruits-nuts 5,829 (10.1) 3,279 (9.2) 177 (11.8) 213 (4.4) 2,160 (14.1)

Vegetables† 16,057 (27.9) 9,070 (25.3) 108 (7.2) 8 (0.2) 6,871 (45.0)

Fungi 37 (0.1) 14 (0.0) 23 (1.5)

Leafy 7,769 (13.5) 2,393 (6.7) 55 (3.7) 7 (0.1) 5,314 (34.8)

Root 1,501 (2.6) 793 (2.2) 7 (0.5) 700 (4.6)

Sprout 713 (1.2) 713 (2.0)

Vine-stalk 6,038 (10.5) 5,157 (14.4) 22 (1.5) 1 (0.0) 857 (5.6)

Undetermined 4,639 (8.1) 124 (0.3) 4,428 (90.6) 87 (0.6)

Total 57,462 (100.0) 35,797 (100.0) 1,496 (100.0) 4,886 (100.0) 15,284 (100.0)

9

16. Which of the following does not apply to parasitic protists? Circle all that apply. (2 points)

a. Has RNA and DNA

b. Are not animal, plant, or fungus

c. Require a host for reproduction

d. Diseases they cause can be treated with antibiotic

17. According to the table, which of the following are commodity groups? Circle all that apply. (2

points)

a. Plants

d. Beef

e. Aquatic Animals

f. Shellfish

18. Which single commodity (i.e. not group) listed in the table caused the most hospitalization?

(2 points)

Dairy

19. For the Leafy commodity listed in the table which agent caused the most hospitalization (a) and

which specific organism was the most likely the highest contributor to that agent (b). (3 points)

a. Virus --- 1 point

b. Norovirus --- 2 points

20. For the Fish commodity, chemical/toxin agents caused the most hospitalization. Name a type of

food borne disease caused by chemical/toxins when eating fish (a), symptoms associated with

the disease (b), and the cause of the toxins (c). (3 points) TIEBREAKER 3

a. Ciguatera or scombroid or shellfish toxin or puffer fish or mercury/ --- 1 point

b. gastrointestinal illness and may also cause neurologic symptoms/ acute allergic

reaction/paralysis/paralysis/mercury associated --- 1 point

c. toxin made by dinoflagellates such as Gambierdiscus toxicus (algae)/ naturally high levels

of histidine (converted to histamine)/toxin made by algae/Tetrodotoxin/environment --- 1

points

On March, 10th, 2014 the Wisconsin Department of Health was informed of an outbreak of gastro-intestinal illness in the pediatric ward of the hospital in Milwaukee. 25 people, 15 patients and 10 staff members from the pediatric ward had reportedly fallen ill since February 19th. Symptoms included cramps, diarreah, and vomiting. Laboratory testing of stool samples of the affected individuals showed the presence of Campylobacter jejuni, which has an incubation time of 2-5 days. The health department immediately started an investigation. The investigators defined a case as a patient or member of staff of pediatric ward who developed diarrhea, cramps, vomiting and tested positive for Campylobacter jejuni between February 19th and March 10th 2014. The investigators suspected a single food source to the culprit.

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21. Why do you think the health department decided to investigate the outbreak? Circle all that apply. (2 points) a. Identify the source and eliminate it b. Develop strategies to prevent further outbreaks c. Evaluate existing preventative measures d. To learn more about C.jejuni infections

22. What is the term for a disease occurring or acquired in a hospital setting? (1 point)

Nosocomial

23. In order the classify a case associated with this outbreak as possible, probable, or confirmed, investigators most likely organized data into what type of table? (1 point) Line listing

The following data was collected:

Date of onset

19-Feb 20-Feb 21-Feb 22-Feb 23-Feb

Number of cases

3 7 10 4 1

24. Draw an epicurve using the above table. Make sure to include every necessary information on the graph. Please note that no other cases were reported prior to 19-Feb and after 23-Feb. (8 points) Correct label of x- and y-axis as well as title, appropriate scale (1/4 of 2-5 days, pick average incubation time of 1 day for x-axis) --- 2 points for correct graph, 1 point per each axis label, 2 points for correct scale, 2 points for correct title)

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25. What type of outbreak does your epi curve indicate (a)? Does this support the suspicion of a single food source as the culprit (b)? Explain your answer. (2 points) a. Point source --- 1 point b. Yes as point source is indicative of single exposure --- 1 for correct answer/explanation

26. The investigators are suspecting that all affected individuals consumed the contaminated food

on the same date. On what date was the contaminated food most likely consumed? Explain your answer. (3 points) Feb. 17 due to single point source, incubation time, and first and last cases --- 2 points for date, 1 points for correct explanation

One common source of Campylobacter jejuni food poisoning is raw or undercooked chicken. The investigators decided to conduct a study to determine if chicken that was served at the pediatric ward the days preceding the outbreak was the culprit. The investigators were able to gather information about all patients and staff in terms of whether they had eaten the chicken or not. They decided to compare confirmed cases who ate chicken with patients and staff who also ate the chicken but did not become ill. Of the 25 confirmed cases, 23 reported to have eaten chicken. Of the patients and staff who did not become ill, 42 reported to have eaten the chicken. There were a total of 90 patients and staff in the pediatric ward during the days preceding the outbreak.

27. What type of study is this? Circle all that apply. (2 points) a. Cross-sectional b. Experimental c. Observational d. Case-control

28. Arrange the information from the above paragraph into a meaningful 2X2 table. (4 points)

Cases Controls

Exposed (ate chicken) 23 42 Not exposed (did not eat chicken) 2 23

29. What can you calculate from the table (a), perform the calculation (b), and interpret the result (c). (5 points) a. Odds ration --- 1 point b. (23/42)/(2/23) = 6.11--- 2 points c. People of having eaten the chicken are 6.11 times more likely to become sick than people

who did not. Supports hypothesis that chicken was culprit. --- 2 points Give half credit for RR.

30. How do you explain the two confirmed cases that did not eat the chicken? (3 points) Take any

reasonable explanation

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