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DISEASE DETECTIVES WESO 2014 Supervisor: John Nicklas.

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Presentation on theme: "DISEASE DETECTIVES WESO 2014 Supervisor: John Nicklas."— Presentation transcript:

1 DISEASE DETECTIVES WESO 2014 Supervisor: John Nicklas

2 Brief Description Objective: The goal of the Disease Detectives event is to have students understand connections between things they may encounter in daily life and various health problems that affect communities, risks for disease/injury, and opportunities for prevention. Brief description: Students will be tested on their knowledge, observational, analytical, and investigative skills in the study of disease, risk, spread, and prevention in populations or groups of people with a focus on food borne causes of public health problems. 2014 Focus: FOOD-BORNE ILLNESS

3 The Competition Grades: 2, 3, 4 and 5
Number of participants: up to 3 students Time: 30 mins Test format: A team of 1-3 students will be tested through a written test, analysis of material at observation tables, or a combination of both. Question format: The question format may include, but not be limited to multiple choice questions, fill in the blanks, true or false, matching, and/or short answers. All questions will be grade appropriate. Any calculations and mathematical manipulations will be consistent with grade level math skills. Students do not need to show their work. There will be no partial credit. Observation table format: Students may observe an object, a picture, a table, a graph, a diagram, narrative information, and/or a short video. There will be specified questions in the test regarding the material presented at each observation station. Event parameters: A standard #2 pencil, lined notepaper, and answer sheets will be provided by the supervisor. Grades 2 and 3 will NOT need calculators. WESO will provide Grades 4 and 5 with a calculator (non-graphing, non-­programmable). A reference sheet will not be allowed. Scoring: The highest number of correct answers determines the winner. Tie Breaker: Pre-selected test questions will be used as tiebreakers. In the event that all tiebreaker questions are answered correctly, time will be used as a tiebreaker.

4 About this PowerPoint This is just a study guide; it does not include all the necessary info students will need to know. Everything that applies only to 4th and 5th Graders is labeled as such on the slide. All other slides are meant for all grades.  (Grades 4 and 5) The emphasis this year is on concepts (such as epi-curves and cohort/case control studies), not on memorizing information (general and specific pathogens).

Role and Examples of Disease Detectives Outbreak Investigation (Scientific Method) Problems investigated by Disease Detectives Basic Epidemiological Terms Types of Pathogens Modes of Transmission – Agent/Host/Environment Risk Factors - Time/Person/Place Interpreting simple data: narrative, tables, charts, maps, graphs (bar and line) Control and Prevention Strategies

6 Define and Identify Cases Make a Table from a Line Listing
STUDY GUIDE FOR DISEASE DETECTIVES 2014 Extra Stuff for 4th and 5th Graders: Define and Identify Cases Make a Table from a Line Listing Cohort vs. Case Control - Analytical Studies Calculate Measures of Risk Analyze an Epi Curve Characteristics of Specific Foodborne Pathogens

7 Role of Disease Detectives
Who are Disease detectives? Epidemiologists, medical professionals (physicians, veterinarians, nurses), laboratory scientists, statistician, environmental specialists. Role of a disease detective? Collecting and comparing data on various diseases or infections within communities – health of populations, not individuals. Definition and Role of: EPA - Environmental Protection Agency (USEPA) CDC – Centers for Disease Control and Prevention

8 Scientific Method as Related to Disease Detectives
Students need to be familiar with the steps and their importance: (Grades 2 & 3: understand; Grades 4 & 5: understand and apply) Obtain Background Information Define the Problem (and confirm its existence by proper diagnosis in case of an infection) Formulate Hypothesis (For infectious agents: Agent /host/environment = agent capable of causing disease & its source host or persons susceptible to agent + environment allowing them to get together) Develop a Study to Test the Hypothesis Collect Data and Observations Evaluate Results Determine if Hypothesis is true/modify Formulate Conclusions Implement control and preventative measures Report Results

9 Problems Investigated by a Disease Detective
chronic diseases heart disease, cancer, diabetes,… environmental problems allergies, pollution, radiation, lead, mercury,… behavioral problems obesity, stress, lack of sleep,… injuries violence, occupation, sports, transportation,… infectious diseases influenza, chicken pox,… Foodborne Illness

10 Basic Epidemiological Terms
Grades 2 and 3: agent, case report, case series, chain of infection, cluster, contamination, endemic, environment, epidemic, epidemiology, fomite, host, hygiene, immunity, infection, infectious, outbreak, outcome, pandemic, pathogen, pathogenic, pattern, public health surveillance, risk, susceptible, symptom, trend, vector, vehicle, virulent. Grades 4 and 5: attack rate, case control, cohort, control group, epi curve, exposure, gram stain, incidence, incubation, index case, infectivity, mortality, odds ratio, onset, prevalence, period, relative risk, reservoir, virulence, zoonosis, AND Grade 2/3 terms.

11 Types of Pathogens viruses bacteria protists (protozoa) fungi animals (worms) natural toxins, chemicals prions Basic characteristics: definition, structure, morphology, identification, motility, types, habitat, a few common examples, any unique features. Grades 4 & 5: also how to destroy, diet, route of entry.

12 Example of info needed for a general pathogen:
Bacteria Definition Prokaryotic, unicellular microorganisms. Structure Have cell walls but lack organelles and an organized nucleus. Morphology / Types Typically .5 to 5.0 µm. Can be spherical (cocci), rod-shaped (bacilli), comma (vibrio), or spiral (spirilla). Arranged in pairs (di), lines (strep), or clusters (staph). Identification Looks like: or Motility Flagella – swim through fluids. Bacterial gliding, twitching motility – move across surfaces. Habitat Practically everywhere: our guts, soil, water, acidic hot springs, radioactive waste, the deep portions of Earth's crust. Common Examples E. Coli, V. Cholerae, C. jejuni, Salmonella, Tuberculosis, Strep Throat, pneumonia, Pertussis (Whooping Cough), Lyme Disease. Unique Features Reproduce by binary fission, can be divided into gram positive and gram negative based on cell membrane. Destroy Heat/cold, antibiotics, silver, chlorine, bleach Diet Sunlight, inorganic compounds, organic compounds, CO2. Route of Entry Oral, respiratory, open wound, bodily fluids. DON’T LEARN All two-dozen phyla or two hundred genera of bacteria.

13 Modes of Transmission Contact: Direct Indirect Droplet Non-contact: Airborne Vehicle (foodborne) Vector

14 Agent/Host/Environment
pathogen & its source Host persons susceptible to agent Environment allows them to get together Outbreak

15 Define and Identify Cases (4th and 5th Grade)
Case definition – establish the standard criteria for determining who has the disease or condition – who’s in this outbreak? Clinical information – about the disease or condition Characteristics - of the affected people Location or place - as specific as possible as restaurant, county, or several specific areas Time sequence - specific time during which the outbreak or condition occurred Identification of cases – kind & number – count specific cases Confirmed – have diagnosis with case definition plus lab verification Probable – many factors point to diagnosis but may lack lab verification Possible – some factors point to diagnosis Note: Initial reports may be only a small sampling of the total problem. Be sure to expand search to determine the true size and extent of the problem

16 Make a Table from a Line Listing (4th and 5th Grade)
Line Listing – list of all the patients in outbreak, with all the relevant info included. Ex: twelve case report forms on a E. Coli outbreak. ID # Initials Date Diagnosis Age Sex County Physician Wedding of Onset Confirmed 1 KR 7/24 probable E. Coli 29 M Columbia Goodman Yes 2 DM 7/27 E. Coli M Columbia Baker Yes 3 JG 7/28 probable E. Coli 26 M Columbia Gibbs Yes 4 RD 7/25 E. Coli M King Webster Yes 5 NT 7/29 E. Coli F Columbia Stanley Yes AM 7/27 No E. Coli F Clayton Mason Yes JR 7/24 E. Coli 39 M Clayton Smith No IH 7/25 No E. Coli 41 F King Gewertz Yes TJ 7/31 No E. Coli 49 F Clayton Koller No AT 7/28 E. Coli 26 F Columbia Kapur Yes ML 7/29 No E. Coli 36 M King Mohr No DU 7/30 No E. Coli 50 F Columbia Kaminski No Turn this Line Listing into: E. Coli No E. Coli Exposed (at wedding) 6 2 Unexposed (not at wedding) 1 3

17 Risk Factors: Time/Place/Person
Epidemiologic variables: can be observed and/or measured. • Time - the time of illness or of a relevant event. Examples: date of exposure or onset of illness. • Place - the environment in which illness occurs. Examples: place of residence, of work, suspected exposure. • Person - individuals who are infected, ill, or at risk. Examples: age, gender, occupation, high risk condition (AIDS). Look at Possible Risk Factors – Descriptive Studies: (4th and 5th Grade) Analyze distribution of disease by cases or outcome, frequency in population, exposure, time pattern or environmental factor. Case report/case series – case report = single patient, case series = several patients Correlative studies Time series - same population at different times Ecologic relations - specific ecologic factors as diet Cross sectional – survey: participants are selected irrespective of exposure/disease status

18 Data Table EXAMPLE of a simple narrative with a 2 X 2 table format for all grades: (For 2014, the narrative and the 2 X 2 table format will be related to foodborne illness): 400 people attended a special awards dinner. Some persons became ill. The suspected dish was the potato salad. The population at the dinner was then surveyed to determine who became ill. Total number of people who attended the dinner? 400 Number of people who were exposed to the suspected salad? = 180 Number of people who were not exposed to the suspected salad? = 220 Number of people who were exposed to the suspected salad and got disease? 150

19 First divides a group by exposure status, then sees who got sick.
(4th and 5th Grade) Cohort vs. Case Control First divides a group by exposure status, then sees who got sick. retrospective:(historic cohort) starts at exposure in past & moves forward to outcome prospective: starts a present exposure and moves forward in time to outcome Calculate: attack rate and relative risk Works backward from effect or illness to suspected cause. Control group is a selected group who has similar characteristics to the sick group but is not ill. They are then checked for similar exposures - hard. Calculate: odds and odds ratio

20 Calculating Measures of Risk: Cohort (4th and 5th Grade)
400 people attended a special awards dinner. Some persons became ill. The suspected dish was the potato salad. The population at the dinner was then surveyed to determine who became ill. Attack rate (4th and 5th grades): the rate that a group experienced an illness. (Look for high attack rate in exposed & low rate in unexposed) = number of people sick ÷ total in that group. Attack rate for exposed individuals = 150 ÷180 = (83.3%) a/(a+b) Attack rate for unexposed individuals = 50 ÷220 = (22.7%) c/(c+d) Relative risk (5th grade): estimates the extent of the association between an exposure and a disease. It estimates the likelihood of developing the disease in the exposed group as compared to the unexposed group. A relative risk >1.0 indicates a positive association or an increased risk. A relative risk = 1.0 indicates that the incidence rates of disease in the exposed group is equal to the incidence rates in unexposed group. Therefore the data does not provide evidence for an association. Relative risk= Attack rate for exposed ÷ Attack rate for unexposed = 83.3% ÷ 22.7% = 3.66. [a/(a+b)]/[c/(c+d)]=a(c+d)/c/(a+b) (a) (b) (c) (d)

21 Calculating Measures of Risk: Case-Control (4th and 5th Grade)
200 people arrived at the emergency room, all complaining of severe stomach cramps. The suspected cause was contaminated jello-pudding served at a recent dinner party. A control group was then found from among those dinner party guests who did not become ill. Odds (4th and 5th grades): the odds that a certain group was exposed to a risk factor. = number of people exposed ÷ number of people unexposed Odds for cases = 150 ÷50 = 3 a/c Odds for controls = 80 ÷20 = 4 b/d Odds Ratio (5th grade): It estimates how many times more likely those who were exposed were to develop disease. Odds for cases ÷ odds for controls= 3/4 =0.75. [a/c]/[b/d]=ad/bc Therefore, those who ate jello were 0.75 times as likely than those who didn’t eat jello to get sick, or in other words less likely. The real cause of the outbreak was probably something else. Disease Yes (cases) Disease No (controls) Exposed (ate jello) (a) (b) Unexposed (no jello) (c) (d)

22 Epi- Curves (4th and 5th Grade)
An epi-curve is a histogram, displaying frequency of disease on the y-axis and time on the x-axis (units ≈¼ of incubation period). It can tell us about: Pattern of spread Magnitude Outliers Time trend Exposure and/or disease incubation period Students won’t be asked to create, but will be asked to interpret epi-curves.

23 Analyzing Epi- Curves (4th and 5th Grade)
Average Incubation Period: 10 days Outlier: Index Case Minimum Incubation Period: 7 days Likely Period of Exposure: 3 days Magnitude: 73 cases total Time Trend: First case on Day 11, peak # of cases on Day 21, no cases after Day 28

24 Epi- Curves – Patterns of Disease Spread (4th and 5th Grade)
(one-time exposure) (person-to-person)

25 Pertussis Infection by 5-Year Age Groups (
Graphs EXAMPLE of a Bar Graph: (For 2014, the graphs will be related to foodborne illness) Pertussis Infection by 5-Year Age Groups ( Which age group has the largest number of cases? 0-4 True or False: As you grow older, the incidence of pertussis infection decreases (True).

26 Line Graphs EXAMPLE of a Line graph:
How many TB cases were there in the United States in 2001? About 10,000 About 25,000 About 16,000 Cannot tell from the Figure Answer: c Which of the following statements is false? There were more Tuberculosis (TB) cases in 1993 than in 1984. For the years shown in the Figure, the year with the fewest TB cases was 2001. For the years shown in the Figure, the only year when there were fewer than 20,000 TB cases was 1999. Answer: c

27 Control and Prevention Strategies
Act as soon as source is known – people are sick or hurting and need help; must know agent & source of agent + susceptibility of host + chain of transmission Aim at chain of agent-source-host – break the chain of transmission at any of its 3 points Interrupt transmission or exposure – isolate vehicles of transmission Reduce susceptibility – with immunization, legal issues and/or education

28 Foodborne Illnesses (4th and 5th Grade)
4th and 5th Grade: specific questions can be based on the following foodborne illnesses: Escherichia coli (E. coli) Campylobacter jejuni (C. jejuni) Vibrio cholerae (V. cholerae) Giardia intestinalis (G. intestinalis) Norovirus Study criteria: type of causative agent, basic characteristics, mode of transmission, foods most associated with the illness, any unique features, symptoms, diagnosis, prevention, treatment, identification, gram stain, incubation period, virulence, infectivity, recent outbreaks, history.

29 An example of info needed for a specific food-borne illness:
(4th and 5th Grade) An example of info needed for a specific food-borne illness:

30 An example of info needed for a specific food-borne illness:
(4th and 5th Grade) An example of info needed for a specific food-borne illness:

31 Useful Links National Science Olympiad - The focus is on the training handout/PowerPoint, but the test will not cover everything on this sheet. Make sure that the info is grade-level appropriate and the topic is covered in this PowerPoint before handing the info out. Practice Tests - Again, I won't cover everything asked on these tests. Coaches must check to make sure that each question is grade level appropriate and covered in the WESO DD PowerPoint/Study Guide before they hand out these exams. Public Health Teaching Resources - Links to other sites, teaching exercises, and more. Make sure they are grade-level appropriate and the topic is covered in this PowerPoint before handing them out. (Grades 4 and 5) Foodborne Illnesses - Here is a good place to start searching for info about the five specific foodborne pathogens mentioned on slide 28. Students don’t need to learn about the others. (Grades 4 and 5) Cohort / Case Control - The emphasis is on being able to identify a given study as either a cohort or a case control.

32 Fun Links and Questions
Fun Links: ANY QUESTIONS?? Please Subject: Disease Detectives


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