Kraemer Science Olympiad Invitational Disease Detectives Test January 2017

Transcription

1 Kraemer Science Olympiad Invitational Disease Detectives Test January 2017 Student Names: School Name and Number: For the supervisor: Part 1 Score: (of 30) Part 2 Score: (of 30) Part 3 Score: (of 62) Part 4 Score: (of 36) Total Score: (of 158) Place: Good luck! 1

2 Part I: Vocabulary 1. In a, scientists compare people with and without symptoms to look for common exposures. 2. When calculating case-fatality rate, the is in the numerator and the is in the denominator. 3. In a type of outbreak, many people are exposed to a common source of disease over a short period of time. 4. A is a place where agents can survive and reproduce. 5. is the transmission of an infectious agent through aerosols produced in sneezing, coughing, or talking. 6. describes the interaction of raw meat and cooked product. 7. A disease is described as if it is consistently present at high levels in an area. 8. A distribution has two peaks. 9. A study where the exposure and outcomes have already happened is referred to as. 10. An animal infection that spreads to humans is called a. Part II: Multiple Choice 1. How many people contract food borne illness every year in the United States? A. 27 million B. 36 million C. 48 million D. 59 million 2. Which of the following is caused by a virus? A. Cholera B. Botulism C. Salmonella D. Hepatitis A 2

3 3. Which bacteria frequently causes premature delivery in pregnant women? A. Listeria Monocytogenes B. Campylobacter Jejuni C. Salmonella Enterica D. Staphylococcus Aureus 4. Pregnant women can avoid the bacteria from #3 by not eating A. Potato Salad B. Canned Foods C. Unwashed Produce D. Deli Meat 5. Which of the following is most commonly caused by norovirus? A. Colitis B. Gastroenteritis C. Guillan-Barré Syndrome D. Cyclosporiasis 6. The majority of E. coli cases have what cause? A. Food B. Water C. Animal or environmental interaction D. Person-to-person contact 7. About how many deaths are caused by foodborne illness in the United States every year? A. 130,000 B. 13,000 C. 3,100 D In 2009, there were new cases per 100,000 people in the US of Campylobacter jejuni. This represents a measure of: A. Mortality B. Mortality rate C. Incidence D. Incidence Rate E. Prevalence F. Prevalence Rate 3

4 9. How many deaths happen from foodborne illness worldwide every year? A. 4,200,000 B. 2,100,000 C. 840,000 D. 420,000 E. 105, Which of the following chemicals is used most often to clean surfaces? A. Sodium chloride B. Ammonia C. Chlorine D. Hydrogen peroxide E. Iodine 11. Botulinum toxin causes... A. Asymmetric descending paralysis B. Symmetric descending paralysis C. Asymmetric ascending paralysis D. Symmetric ascending paralysis 12. Which of the following is a Gram-positive, rod-shaped bacterium? A. Cryptosporidium B. Staphylococcus Aureus C. E. Coli D. Listeria Monocytogenes 13. Which of the following statements is/are true? I. Shigella, a virus, needs a host cell in order to reproduce. II. Campylobacter Jejuni, a bacterium, is a prokaryotic, living cell. III. Listeria Monocytogenes can cause meningitis in elderly or otherwise immunocompromised people. A. I only B. II only C. II and III D. I and III E. None of the above statements are true. 14. Which of the following statements represent advantages of case-control studies? I. They are very accurate. II. They are relatively cheap. III. They rely too much on memory. IV. They accurately cover exposure. V. They can study rare diseases. 4

5 15. Which of the following statements is accurate? A. Morbidity refers to death whereas mortality refers to disease. B. Mortality refers to death whereas morbidity refers to disease. C. Both morbidity and mortality refer to death. D. Both morbidity and mortality refer to disease. 16. Which of the following is not considered a property of an agent? A. Virulence B. Efficiency C. Pathogenicity D. Infectivity 17. Most steps taken by the CDC can be described as: A. Primary prevention B. Secondary Prevention C. Tertiary Prevention D. Quaternary Prevention E. Dromedary Prevention 18. Which of the following statements is accurate? A. Quarantine is the separation of unexposed people whereas isolation is the separation of healthy people. B. Quarantine is the separation of unexposed people whereas isolation is the separation of ill people. C. Quarantine is the separation of exposed people whereas isolation is the separation of healthy people. D. Quarantine is the separation of exposed people whereas isolation is the separation of ill people. E. Quarantine and isolation are only practiced by the TSA. 19. Which of the following statements is accurate? A. Humans can be hosts but not reservoirs. B. Humans can be reservoirs but not hosts. C. Humans can be both reservoirs and hosts. D. Humans can be neither reservoirs nor hosts. E. Beavers are hosts of reservoirs. 20. The mode of transmission for foodborne illnesses is usually: A. Airborne B. Direct C. Droplet D. Food E. Vehicle F. Vector 5

6 Part III: Passage The following passage and questions are adapted from the CDC. Notes from the Field: Clostridium perfringens Gastroenteritis Outbreak Associated with a Catered Lunch North Carolina, November 2015 During November 2015, the North Carolina Division of Public Health was notified by the Pitt County Health Department (PCHD) that approximately 40 persons who attended a catered company Thanksgiving lunch the previous day were ill with diarrhea and abdominal pain. Within hours of notification, investigators developed and distributed an online survey to all lunch attendees regarding symptoms and foods consumed and initiated a cohort study. A case of illness was defined as abdominal pain or diarrhea in a lunch attendee with illness onset <24 hours after the event. Risk ratios (RRs) were estimated for all menu items. Among 80 attendees, 58 [A %] completed the survey, including 44 respondents [B %] who reported illnesses meeting the case definition; among these, 41 [C %] reported diarrhea, and 40 [D %] reported abdominal pain. Symptom onset began a median of 13 hours after lunch, ranging from 1 to 22 hours. Among the 44 persons who ate turkey or stuffing, which were plated and served together, 38 [E %] met the case definition; among the 14 who did not eat turkey or stuffing, 6 [F %] reported illness. PCHD collected stool specimens from ill persons and samples of leftover food from the company that hosted the lunch. Stool specimens were tested for norovirus and bacterial enteric pathogens at the North Carolina State Laboratory for Public Health. Based on reported symptoms and short interval between the lunch and symptom onset, a toxin was suspected as the cause of the outbreak; therefore, five stool specimens from ill persons and 20 food samples were submitted to CDC for Clostridium perfringens detection. Stools were tested for C. perfringens enterotoxin (CPE) using reversed passive latex agglutination. Stool culture and enumeration of C. perfringens colony forming units (CFU) were performed for five samples of foods implicated by the epidemiologic investigation (one stuffing sample and four turkey samples). Because meat is the most common source of C. perfringens outbreaks, one ham sample also was analyzed, although consumption of ham was not associated with an increased risk for illness. CPE was detected in all five stool specimens. C. perfringens containing the C. perfringens enterotoxin gene (cpe) was recovered from all five stool specimens and from all four turkey samples; one turkey sample contained >105 CFU/g. C. perfringens was not recovered from samples of other foods. No other pathogens were detected in stool specimens. Collectively, laboratory results met CDC guidelines for confirming C. perfringens as the outbreak source. PCHD environmental health specialists interviewed the caterer about food handling and preparation practices. The North Carolina Food Code requires that all commercial caterers operate in a facility that has been inspected for compliance and permitted by the regulatory authority. The caterer had previously maintained a permitted facility, but reported having prepared the lunch food served at this event in an uninspected, residential kitchen. Turkeys were cooked approximately 10 hours before lunch, placed in warming pans, and plated in individual servings. Food was then delivered by automobile, which required multiple trips. After cooking and during transport, food sat either in warming pans or at ambient temperature for up to 8 hours. No temperature monitoring was conducted after cooking. C. perfringens toxicoinfection is often associated with consumption of meat that has been improperly prepared and handled. Because diagnostic testing is not widely available, C. perfringens can go undetected as a cause of foodborne illness outbreaks. Diagnostic testing to assist with outbreak source identification is useful to corroborate epidemiologic information, document disease prevalence, and guide prevention recommendations. 6

7 Passage Analysis Questions: 1. In the first paragraph, letters A - G denote relevant percentages. Provide the correct responses below, in whole percent amounts: A: D: B: E: C: F: 1b. Create a 2x2 table showing the data from parts E and F. 2. Calculate the relative risk for those that consumed the turkey and/or stuffing, and explain your findings. 3. Take the percentage represented by F in question 1. Give the name of the statistic that defines (1 - F). 4. Name the two symptoms of C. perfringens as described in the article. 5. What type of pathogen (bacteria, fungus, prion, protozoan, virus) causes C. perfringens? 7

8 6. What is a stool sample? 7. Name the four parts of a case definition. 8. Provide a case definition for the passage above. 9. The passage defines the grouping of illnesses as an outbreak. Define the term. 10. Which of the following rules was violated by the caterers? a. Wash your hands b. Separate raw and cooked food c. Cook food thoroughly d. Keep food at safe temperatures e. Use safe water and raw materials f. Report all possible outbreaks immediately g. Treat others how you want to be treated. 11. What is the minimum temperature at which turkey should be cooked to ensure safety? 12. The passage references a unit of measurement abbreviated as CFU/g. Define and describe it. 8

9 13. The first paragraph states, Symptom onset began a median of 13 hours after lunch, ranging from 1 to 22 hours. Give the name for the term describing the time between contact with a pathogen and symptom onset. 14. An enterotoxin affects which area of the body? a. Stomach b. Liver c. Intestines d. Pancreas e. Elbow 15. [Tiebreaker] Provide 3 ideas showing how the outbreak could have been prevented. Part IV: Random 1. Each of the following describes an action a Disease Detective might take while investigating an outbreak. Give a number (1-10) for the step in the 10-step method that would correspond to this action. Numbers may be repeated or never used. A. Create an Epi Curve B. Generate a Case Definition C. Perform a Case-Control Study D. Publish an academic paper/report on the outbreak E. Ask for laboratory confirmation F. CDC issues new national health guidelines G. Buy equipment for field study 9

10 2. Which of the following diseases causes abnormally small and stubby hands and fingers? A. Achalasia B. Afibrinogenemia C. Acrodysostosis D. Amyloidosis 3. Write out the following acronyms: CDC: AIDS: MRSA: NIH: 4. Name a disease that has been eradicated: 5. In which country did the most recent ebola outbreak begin? 6. Who is the secretary of the Department of Health and Human Services? 10

11 Kraemer Science Olympiad Invitational Disease Detectives Test January 2017 Student Names: School Name and Number: For the supervisor: Score Place: Good luck!

12 Part I: Vocabulary Part II: Multiple Choice

13 Part III: Passage Questions 1. 1b. A. % B. % C. % D. % E. % F. % 2. Risk:

14

15 Part IV: Random 1. A. Create an Epi Curve B. Generate a Case Definition C. Perform a Case-Control Study D. Publish an academic paper/report on the outbreak E. Ask for laboratory confirmation F. CDC issues new national health guidelines G. Buy equipment for field study CDC: AIDS: MRSA: NIH:

16 Kraemer Science Olympiad Invitational Disease Detectives Test January 2017 Student Names: School Name and Number: For the supervisor: Score Place: Good luck! KEY

17 Part I: Vocabulary [3 points each; 1 point for spelling mistakes that are recognizable] 1. In a, scientists compare people with and without symptoms to look for common exposures. (case-control study) 2. When calculating case-fatality rate, the is in the numerator and the is in the denominator. (number of deaths; number of cases) 3. In a type of outbreak, many people are exposed to a common source of disease over a short period of time. (point-source) 4. A is a place where agents can survive and reproduce. (reservoir) 5. is the transmission of an infectious agent through aerosols produced in sneezing, coughing, or talking. (droplet spread) [no partial credit] 6. describes the interaction of raw meat and cooked product. (cross-contamination) 7. A disease is described as if it is consistently present at high levels in an area. (hyperendemic) 8. A distribution has two peaks. (bimodal) 9. A study where the exposure and outcomes have already happened is referred to as. (retrospective) 10. An animal infection that spreads to humans is called a. (zoonosis) TOTAL: /30. Part II: Multiple Choice [1.5 points each] 1. How many people contract food borne illness every year in the United States? A. 27 million B. 36 million C. 48 million D. 59 million 2. Which of the following is caused by a virus? A. Cholera B. Botulism C. Salmonella D. Hepatitis A 3. Which bacteria frequently causes premature delivery in pregnant women? A. Listeria Monocytogenes B. Campylobacter Jejuni

18 C. Salmonella Enterica D. Staphylococcus Aureus 4. Pregnant women can avoid the bacteria from #3 by not eating A. Potato Salad B. Canned Foods C. Unwashed Produce D. Deli Meat 5. Which of the following is most commonly caused by norovirus? A. Colitis B. Gastroenteritis C. Guillan-Barré Syndrome D. Cyclosporiasis 6. The majority of E. coli cases have what cause? A. Food B. Water C. Animal or environmental interaction D. Person-to-person contact 7. About how many deaths are caused by foodborne illness in the United States every year? A. 130,000 B. 13,000 C. 3,100 D In 2009, there were new cases per 100,000 people in the US of Campylobacter jejuni. This represents a measure of: A. Mortality B. Mortality rate C. Incidence D. Incidence Rate E. Prevalence F. Prevalence Rate 9. How many deaths happen from foodborne illness worldwide every year? A. 4,200,000 B. 2,100,000 C. 840,000 D. 420,000 E. 105, Which of the following chemicals is used most often to clean surfaces? A. Sodium chloride B. Ammonia C. Chlorine D. Hydrogen peroxide E. Iodine

19 11. Botulinum toxin causes... A. Asymmetric descending paralysis B. Symmetric descending paralysis C. Asymmetric ascending paralysis D. Symmetric ascending paralysis 12. Which of the following is a Gram-positive, rod-shaped bacterium? A. Cryptosporidium B. Staphylococcus Aureus C. E. Coli D. Listeria Monocytogenes 13. Which of the following statements is/are true? I. Shigella, a virus, needs a host cell in order to reproduce. II. Campylobacter Jejuni, a bacterium, is a prokaryotic, living cell. III. Listeria Monocytogenes can cause meningitis in elderly or otherwise immunocompromised people. A. I only B. II only C. II and III D. I and III E. None of the above statements are true. 14. Which of the following statements represent advantages of case-control studies? I. They are very accurate. II. They are relatively cheap. III. They rely too much on memory. IV. They accurately cover exposure. V. They can study rare diseases. 15. Which of the following statements is accurate? A. Morbidity refers to death whereas mortality refers to disease. B. Mortality refers to death whereas morbidity refers to disease. C. Both morbidity and mortality refer to death. D. Both morbidity and mortality refer to disease. 16. Which of the following is not considered a property of an agent? A. Virulence B. Efficiency C. Pathogenicity D. Infectivity 17. Most steps taken by the CDC can be described as: A. Primary prevention B. Secondary Prevention C. Tertiary Prevention D. Quaternary Prevention E. Dromedary Prevention 18. Which of the following statements is accurate? A. Quarantine is the separation of unexposed people whereas isolation is the separation of healthy people. B. Quarantine is the separation of unexposed people whereas isolation is the separation of ill people. C. Quarantine is the separation of exposed people whereas isolation is the separation of healthy people.

20 D. Quarantine is the separation of exposed people whereas isolation is the separation of ill people. E. Quarantine and isolation are only practiced by the TSA. 19. Which of the following statements is accurate? A. Humans can be hosts but not reservoirs. B. Humans can be reservoirs but not hosts. C. Humans can be both reservoirs and hosts. D. Humans can be neither reservoirs nor hosts. E. Beavers are hosts of reservoirs. 20. The mode of transmission for foodborne illnesses is usually: A. Airborne B. Direct C. Droplet D. Food E. Vehicle F. Vector Total: /30. Part III: Passage The following passage and questions are adapted from the CDC. Notes from the Field: Clostridium perfringens Gastroenteritis Outbreak Associated with a Catered Lunch North Carolina, November 2015 During November 2015, the North Carolina Division of Public Health was notified by the Pitt County Health Department (PCHD) that approximately 40 persons who attended a catered company Thanksgiving lunch the previous day were ill with diarrhea and abdominal pain. Within hours of notification, investigators developed and distributed an online survey to all lunch attendees regarding symptoms and foods consumed and initiated a cohort study. A case of illness was defined as abdominal pain or diarrhea in a lunch attendee with illness onset <24 hours after the event. Risk ratios (RRs) were estimated for all menu items. Among 80 attendees, 58 [A %] completed the survey, including 44 respondents [B %] who reported illnesses meeting the case definition; among these, 41 [C %] reported diarrhea, and 40 [D %] reported abdominal pain. Symptom onset began a median of 13 hours after lunch, ranging from 1 to 22 hours. Among the 44 persons who ate turkey or stuffing, which were plated and served together, 38 [E %] met the case definition; among the 14 who did not eat turkey or stuffing, 6 [F %] reported illness. PCHD collected stool specimens from ill persons and samples of leftover food from the company that hosted the lunch. Stool specimens were tested for norovirus and bacterial enteric pathogens at the North Carolina State Laboratory for Public Health. Based on reported symptoms and short interval between the lunch and symptom onset, a toxin was suspected as the cause of the outbreak; therefore, five stool specimens from ill persons and 20 food samples were submitted to CDC for Clostridium perfringens detection. Stools were tested for C. perfringens enterotoxin (CPE) using reversed passive latex agglutination. Stool culture and enumeration of C. perfringens colony forming units (CFU) were performed for five samples of foods implicated by the epidemiologic investigation (one stuffing sample and four turkey samples). Because meat is the most common source of C. perfringens outbreaks, one ham sample also was analyzed, although consumption of ham was not associated with an increased risk for illness. CPE was detected in all five stool

21 specimens. C. perfringens containing the C. perfringens enterotoxin gene (cpe) was recovered from all five stool specimens and from all four turkey samples; one turkey sample contained >105 CFU/g. C. perfringens was not recovered from samples of other foods. No other pathogens were detected in stool specimens. Collectively, laboratory results met CDC guidelines for confirming C. perfringens as the outbreak source. PCHD environmental health specialists interviewed the caterer about food handling and preparation practices. The North Carolina Food Code requires that all commercial caterers operate in a facility that has been inspected for compliance and permitted by the regulatory authority. The caterer had previously maintained a permitted facility, but reported having prepared the lunch food served at this event in an uninspected, residential kitchen. Turkeys were cooked approximately 10 hours before lunch, placed in warming pans, and plated in individual servings. Food was then delivered by automobile, which required multiple trips. After cooking and during transport, food sat either in warming pans or at ambient temperature for up to 8 hours. No temperature monitoring was conducted after cooking. C. perfringens toxicoinfection is often associated with consumption of meat that has been improperly prepared and handled. Because diagnostic testing is not widely available, C. perfringens can go undetected as a cause of foodborne illness outbreaks. Diagnostic testing to assist with outbreak source identification is useful to corroborate epidemiologic information, document disease prevalence, and guide prevention recommendations. Questions: 1. In the first paragraph, letters A - G denote relevant percentages. Provide the correct responses below, in whole percent amounts: [1 point each] A: 73% D: 91% B: 76% E: 86% C: 93% F: 43% 1b. Create a 2x2 table showing the data from parts E and F. [4 points - 1 for each box] Diseased (yes/no); Y-axis: Exposed (Yes/no) Calculate the relative risk for those that consumed the turkey and/or stuffing, and explain your findings. a) 2.02 b) The relative risk is greater than 1. This means that people who ate the turkey and/or stuffing were more likely than the other guests to contract the illness. It also makes it likely that the turkey and/or stuffing caused the outbreak. Scoring: 4 points for Part A (If less than 3 sig figs, give 2 points). 4 points for Part B - 2 for stating guests were more likely to contract disease, 2 for stating turkey was more likely to cause the outbreak.

22 3. Take the percentage represented by F in question 1. Give the name of the statistic that defines (1 - F). [4 points] Negative predictive value (NPV) [2 points for just NPV ] 4. Name the two symptoms of C. perfringens as described in the article. [4 points - 2 for each] Diarrhea; abdominal pain 5. What type of pathogen (bacteria, fungus, prion, protozoan, virus) causes C. perfringens? [2 points] bacteria 6. What is a stool sample? A stool sample is a sample of feces that is used in laboratories to identify possible causes of illness. Scoring: 4 points - 2 for citing feces, 2 for giving scientific use. 7. Name the four parts of a case definition. [4 points - 1 each] Person, place, time, clinical features 8. Provide a case definition for the passage above. Person: Attendees of a company Thanksgiving lunch Place: A company meeting area in Pitt County, North Carolina Time: November 2015 Clinical features: Abdominal pain, diarrhea Scoring: Person - 2 points; remove 1 for missing references to company or Thanksgiving lunch Place - 2 points - remove 1 for missing references to Pitt County or North Carolina, or for not specifying that it wasn t the whole county. Time: 2 points - remove 1 without month or year. Around Thanksgiving is acceptable in place of the month. Clinical features - 2 points, 1 for each symptom. 9. The passage defines the grouping of illnesses as an outbreak. Define the term. A sudden increase in occurrences of a disease in a particular time and place Scoring: 2 points - remove 1 if missing references to occurrences, time, or place 10. Which of the following rules was violated by the caterers? [2 points] a. Wash your hands b. Separate raw and cooked food

23 c. Cook food thoroughly d. Keep food at safe temperatures e. Use safe water and raw materials f. Report all possible outbreaks immediately g. Treat others how you want to be treated. 11. What is the minimum temperature at which turkey should be cooked to ensure safety? [4 points] 165 F 12. The passage references a unit of measurement abbreviated as CFU/g. Define and describe it. Colony forming unit per gram. It is a unit to measure the quantity of viable pathogenic cells. Scoring: 6 points. 3 points for listing what it stands for (accept alternate forms of forming ). 3 points for the description, -1 if not referencing that it is a unit or that it measures amount of pathogen. 13. The first paragraph states, Symptom onset began a median of 13 hours after lunch, ranging from 1 to 22 hours. Give the name for the term describing the time between contact with a pathogen and symptom onset. [4 points; give 2 for latency period] Incubation period 14. An enterotoxin affects which area of the body? [4 points] a. Stomach b. Liver c. Intestines d. Pancreas e. Elbow 15. [tiebreaker] Provide 3 ideas showing how the outbreak could have been prevented. [ONLY GRADE IN THE EVENT OF A TIE] Examples: Keep food at a safe temperature after cooking and before serving Monitor temperature to check bacteria growth Cook food closer to event time Educate workers better on food safety and foodborne illness Hire a kitchen manager to supervise similar situations [Other answers will be considered as well]

24 Scoring: In the event of a tie, each correct response up to 3 is worth 0.01 points. Total: / Part IV: Listing Each of the following describes an action a Disease Detective might take while investigating an outbreak. Give a number (1-10) for the step in the 10-step method that would correspond to this action. Numbers may be repeated or never used. [2 points each] A. Create an Epi Curve (5) B. Generate a Case Definition (4) C. Perform a Case-Control Study (7) D. Publish an academic paper/report on the outbreak (10) E. Ask for laboratory confirmation (4) F. CDC issues new national health guidelines (9) G. Buy equipment for field study (1) Which of the following diseases causes abnormally small and stubby hands and fingers? [2 points] A. Achalasia B. Afibrinogenemia C. Acrodysostosis D. Amyloidosis Write out the following acronyms: [3 points each] CDC: (Center for Disease Control) AIDS: (Autoimmune Deficiency Syndrome) MRSA: (Methicillin-resistant Staphylococcus aureus) NIH: (National Institute of Health) Give a disease that has been eradicated: [name 1; 2 points] Smallpox; Rinderpest In which country did the most recent ebola outbreak begin? [2 points] Guinea Who is the secretary of the Department of Health and Human Services? [4 points] Sylvia Matthews Burwell Total: /36. TOTAL POSSIBLE: Tiebreakers, in this order: Part 3, #15 (correct responses up to 3)

25 Number correct in Part 1 Points in Part 3, #8 Points for acronym definition (Part 4) Number correct in 10-step method identification Flip a coin (the school that comes first alphabetically is heads)