DO NOT TURN THE PAGE UNTIL THE EVENT LEADER TELLS YOU TO!

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1 DISEASE DETECTIVES DIRECTIONS DO NOT WRITE ON THIS TEST!! All answers must be written on your response sheet. This test is long. You may wish to divide the test between you. If you take the pages out of the sheet protectors, remember to return the pages in the correct order. Round all answers to the nearest tenth (1 decimal place) unless otherwise noted. Remember to provide units. Answers without units will be marked wrong. Full sentences not required- just make sure your answer makes sense. You may use the back of your response sheets if you need scratch paper Questions are 2 points each unless otherwise noted DO NOT TURN THE PAGE UNTIL THE EVENT LEADER TELLS YOU TO! 1

2 Part 1: General Epidemiology Identify the appropriate study design for each scenario. 1. The usefulness of a new drug for the treatment of malaria needs to be tested. 2. Experts are curious about how prevalent seasonal allergies are in a community. 3. Students at a small school are falling ill and it is suspected that the disease transmitted by food served in the cafeteria. 4. There is an outbreak of dengue fever in several communities, whose populations are difficult to define. Fill in the blank with the appropriate term. 5. A disease that is acquired in a healthcare setting is. 6. A is the term describes the role of a mosquito in the transmission of malaria. 7. The period is the time in which a host is infected by a pathogen but doesn t show symptoms. 8. Becoming immune to a disease after being vaccinated is an example of immunity. Identify the type of agent that describes the organisms that cause the diseases listed. 9. Histoplasmosis, Thrush, Athlete s Foot 10. Mad Cow Disease, Scrapie 11. Common cold, smallpox, mononucleosis 12. Strep throat, MRSA, Legionnaire s Disease Identify the important people given their accomplishments (only need last name). 13. Developed an oral version of the polio vaccine, after Salk developed his polio vaccine. 14. Considered the Father of Modern Epidemiology. 15. Developed a vaccine for rabies, as well as a process of quick heating and cooling used to killed pathogens in food. 16. Ancient who wrote On Airs, Waters, and Places. The oath that doctors take bears his name. 2

3 Given a description, identify the agency (abbreviations only). 17. This international organization monitors disease around the world. 18. This US agency based in Atlanta monitors diseases in the US and issues MMWR. They are the national sponsor for the event. 19. This government agency monitors air quality and sets safety standards for drinking water. 20. This other government agency monitors the safety of food and approves medications List 4 criteria for establishing the association between an exposure and a disease. 3

4 Part 2: Foodborne Disease Outbreaks in United States Schools Based on a 2002 report in the Journal of Pediatric Infectious Disease by Daniels et al. Background. The objective of this study was to describe the epidemiology of foodborne disease outbreaks in schools and to identify where preventive measures could be targeted. Methods. Reports by state and local health departments of foodborne disease outbreaks occurring in primary and secondary schools, colleges and universities from January 1, 1973, through December 31, 1997, were reviewed. Data from ill persons identified through foodborne outbreak investigations and subsequently reported to the Centers for Disease Control and Prevention in the Foodborne Outbreak Surveillance System were examined. The number and size of food- borne disease outbreaks, as well as the etiologic agents, food vehicles of transmission, site of food preparation and contributing factors associated with outbreaks were also examined. Results. From 1973 through 1997, states and local health departments reported 604 outbreaks of foodborne disease in schools. The median number of school outbreaks annually was 25 (range, 9 to 44). In 60% of the outbreaks an etiology was not determined, and in 45% a specific food vehicle of transmission was not determined. Salmonella was the most commonly identified pathogen, accounting for 36% of outbreak reports with a known etiology. Specific food vehicles of transmission were epidemiologically identified in 333 (55%) of the 604 outbreaks. The most commonly implicated vehicles were foods containing poultry (18.6%), salads (6.0%), Mexican-style food (6.0%), beef (5.7%) and dairy products excluding ice cream (5.0%). The most commonly reported food preparation practices that contributed to these school-related outbreaks were improper food storage and holding temperatures and food contaminated by a food handler. Conclusions. Strengthening food safety measures in schools would better protect students and school staff from outbreaks of foodborne illness. Infection control policies could make meals safer for American students List 3 infection control policies that could be introduced. 28. (3) Why is salad among the most commonly implicated vehicles, when all of the other commonly implicated vehicles are animal products? List 2 ways food could have become contaminated other than those listed. (2 each, 4 total) 4

5 Use the following table for questions Notes: Regard each type of Salmonella as a separate agent. Unknown etiology is not an agent 31. Which agent caused the greatest number of outbreaks? 32. What percentage of the outbreaks did that agent cause? 33. Which agent caused the greatest number of illnesses? 34. What percentage of the illnesses did that agent cause? 35. Which agent had the greatest number of hospitalizations? 36. What percent of the total hospitalizations was this? 37. What percentage of outbreaks were caused by chemical agents? 38. What percentage of illnesses were caused by chemical agents? 5

6 Part 3: A Multistate Outbreak of Unknown Etiology Adapted from MMWR May 2010 During May--August 2008, state and local health and agriculture departments, the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS), and CDC investigated two multistate outbreaks of Shiga toxin--producing Escherichia coli O157 (STEC O157) with distinct pulsed-field gel electrophoresis (PFGE) patterns. Investigations into each outbreak included epidemiologic analysis of food exposures, microbiologic testing, and food distribution tracebacks. This report summarizes the results of those investigations. During May 27--August 25, 2008, a total of 99 persons (64 from the first outbreak and 35 from the second outbreak) from 18 states had confirmed illness with an STEC O157 isolate indistinguishable from the outbreak PFGE patterns. 39. What type of study is most appropriate? 40. What is the measure of association used in these types of studies? 41. Write a case definition for this outbreak. This table shows data collected during the investigation: Calculate the appropriate measure of association for each item (1 point each, 13 total): 42. Ground beef purchased only at chain A 43. Raw/bloody/pink ground beef eaten at home 44. Ground beef eaten at home 45. Any exposure to ground beef 46. Lettuce on a sandwich or burger 47. Leafy greens 48. Prepackaged leafy greens 49. House pet contact 50. Spinach 51. Farm animal contact 52. Day care center 53. Ever shopped at chain A 54. Only shopped at chain A 55. Based on this, what exposure do you think is most likely associated with the outbreak? 56. Why? 6

7 Part 4: More General Epidemiology Identify if the following are types of surveillance or not (Yes or no)? 57. Passive 60. Active 58. Healthcare 61. Sentinel 59. Mandated 62. Governmental 63. What is the name for a graph showing the number of cases of disease as a function of time? a. Dose-response function b. Hysteresis curve c. Time-series analysis d. Epidemic curve e. Outbreak graph 64. Can you be vaccinated against bacteria? If a test for Hepatitis C returns an incorrect negative diagnosis for one in every 100 Hepatitis C cases, identify if the following are true or false. (1 pt each) 65. The test has a sensitivity of The test has a specificity of The test has a sensitivity of The test has a specificity of If an exposure is associated with a disease, does that mean that the exposure causes the disease? What is a step that can be taken to reduce or prevent each of the following (list one distinct step for each. Do not use one idea multiple times.) (1 each, 4 total) 70. Recall bias 71. Selection bias 72. Response bias 73. Random error Identify if the following reasons for the successful eradication of smallpox are true or false. 74. There were not many cases of smallpox to begin with. 75. An effective vaccine was available. 76. Smallpox is not contagious 77. People are the only natural reservoirs for smallpox. 78. Only children get smallpox. Two key triads are often mentioned in the context of outbreak investigation. They are: 79. / / 80. / / 81. What is the name for the systematic study of patterns of health and illness in populations? END OF TEST 7

8 Student Response Sheet SCHOOL: V JV1 JV2 JV3 JV4 NAMES:, All Questions are 2 points unless otherwise noted (in parentheses) PART I: GENERAL EPIDEMIOLOGY PART 2: FOODBORNE DISEASE OUTBREAKS IN UNITED STATES SCHOOLS (3) TABLE

9 PART 3: A MULTISTATE OUTBREAK OF UNKNOWN ETIOLOGY (8) EXPOSURE TABLE PART 4: MORE GENERAL EPIDEMIOLOGY 57. YES OR NO 58. YES OR NO 59. YES OR NO 60. YES OR NO 61. YES OR NO 62. YES OR NO 63. A B C D E 64. YES NO SOMETIMES 65. TRUE OR FALSE 66. TRUE OR FALSE 67. TRUE OR FALSE 68. TRUE OR FALSE 69. YES OR NO TRUE OR FALSE 75. TRUE OR FALSE 76. TRUE OR FALSE 77. TRUE OR FALSE 78. TRUE OR FALSE 79. (3) / / 80. (3) / / 81. 9

10 ANSWER KEY SCHOOL: V JV1 JV2 JV3 JV4 NAMES:, All Questions are 2 points unless otherwise noted (in parentheses) 1. CLINICAL OR EXPERIMENTAL TRIAL 2. CROSS-SECTIONAL 3. COHORT 4. CASE-CONTROL 5. NOSOCOMIAL 6. VECTOR 7. INCUBATION 8. ACTIVE 9. FUNGI 10. PRION 11. VIRUS 12. BACTERIA PART I: GENERAL EPIDEMIOLOGY 13. SABIN 14. SNOW 15. PASTEUR 16. HIPPOCRATES 17. WHO 18. CDC 19. EPA 20. FDA LIST ANY 4 OF THE FOLLOWING: STRENGTH OF ASSOCIATION, CONSISTENCY, SPECIFICITY, TEMPORALIFY, BIOLOGICAL GRADIENT, PLAUSIBILITY, COHERENCE, EXPERIMENT (REVERSIBILITY), ANALOGY (ALTERNATE EXPLANATIONS) PART 2: FOODBORNE DISEASE OUTBREAKS IN UNITED STATES SCHOOLS LIST ANY 3: HAND WASHING, KEEP SICK WORKERS HOME, STORE FOOD PROPERLY, COOK FOOD PROPERLY, OTHER EXPLANATIONS POSSIBLE ALLOW ANY THAT MAKE SENSE 28. CROSS-CONTAMINATION LIST ANY 2: FOOD NOT COOKED THOROUGHLY, FOOD CONTAMINATED BY OTHER SOURCES, OTHER ANSWERS POSSIBLE TABLE STAPHYLOCOCCUS AUREUS % 33. STAPHYLOCOCCUS AUREUS % 35. STAPHYLOCOCCUS AUREUS % % % 10

11 PART 3: A MULTISTATE OUTBREAK OF UNKNOWN ETIOLOGY 39. CASE-CONTROL 40. ODDS RATIO 41. (8) 2 POINTS EACH TO LIST INFORMATION ABOUT THE FOLLOWING: TIME, PEOPLE INVOLVED, PLACE, SYMPTOMS EXPOSURE TABLE GROUND BEEF FROM CHAIN A 56. IT HAD THE HIGHEST ODDS RATIO PART 4: MORE GENERAL EPIDEMIOLOGY 57. YES OR NO 58. YES OR NO 59. YES OR NO 60. YES OR NO 61. YES OR NO 62. YES OR NO 63. A B C D E 64. YES NO SOMETIMES 65. TRUE OR FALSE 66. TRUE OR FALSE 67. TRUE OR FALSE 68. TRUE OR FALSE 69. YES OR NO 70. CONDUCT STUDY SOON AFTER OUTBREAK 71. MATCH CASES WITH CONTROLS CAREFULLY 72. MAKE SURE PEOPLE KNOW YOU WILL MAINTAIN CONFIDENTIALITY 73. BE CAREFUL OR AVOID HUMAN ERROR OR UNKNOWN 74. TRUE OR FALSE 75. TRUE OR FALSE 76. TRUE OR FALSE 77. TRUE OR FALSE 78. TRUE OR FALSE 79. (3) AGENT / HOST / ENVIRONMENT (ANY ORDER- CAN BE SWITCHED WITH 80) 80. (3) TIME / PERSON / PLACE (ANY ORDER- CAN BE SWITCHED WITH 79) 81. EPIDEMIOLOGY 11