DISEASE DETECTIVES

WESO 2014

Supervisor: John Nicklas

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

The Competition

Grades: 2, 3, 4 and 5Number of participants: up to 3 studentsTime: 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.

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).

STUDY GUIDE FOR DISEASE DETECTIVES 2014What EVERYONE Needs To Know:

• 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

STUDY GUIDE FOR DISEASE DETECTIVES 2014Extra 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 Pathoge

ns

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

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)

1. Obtain Background Information2. Define the Problem (and confirm its existence by proper diagnosis in

case of an infection)3. 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)

4. Develop a Study to Test the Hypothesis5. Collect Data and Observations6. Evaluate Results 7. Determine if Hypothesis is true/modify8. Formulate Conclusions9. Implement control and preventative measures10. Report Results

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

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.

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.

BacteriaDefinition 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, bleachDiet 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.

Example of info needed for a general pathogen:

Modes of Transmission

Contact:• Direct• Indirect• Droplet

Non-contact:• Airborne• Vehicle (foodborne)• Vector

Agent/Host/Environment

• Agent– pathogen & its source

• Host– persons susceptible to agent

• Environment– allows them to get together

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

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 Confirmed1 KR 7/24 probable E. Coli 29 M Columbia Goodman Yes 2 DM 7/27 E. Coli 33 M Columbia Baker Yes 3 JG 7/28 probable E. Coli 26 M Columbia Gibbs Yes 4 RD 7/25 E. Coli 45 M King Webster Yes 5 NT 7/29 E. Coli 27 F Columbia Stanley Yes 6 AM 7/27 No E. Coli 54 F Clayton Mason Yes7 JR 7/24 E. Coli 39 M Clayton Smith No8 IH 7/25 No E. Coli 41 F King Gewertz Yes9 TJ 7/31 No E. Coli 49 F Clayton Koller No10 AT 7/28 E. Coli 26 F Columbia Kapur Yes11 ML 7/29 No E. Coli 36 M King Mohr No12 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

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

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? 400Number of people who were exposed to the suspected salad? 150 +30 = 180Number of people who were not exposed to the suspected salad? 50 + 170 = 220Number of people who were exposed to the suspected salad and got disease? 150

Disease Yes Disease No Exposed (ate salad) 150 30 Unexposed (no salad) 50 170

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

(4th and 5th Grade)

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 = 0.833 (83.3%) a/(a+b)Attack rate for unexposed individuals = 50 ÷220 = 0.227 (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)

Disease Yes Disease No Exposed (ate salad) 150 30 Unexposed (no salad) 50 170

(a) (b)(c) (d)

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/cOdds for controls = 80 ÷20 = 4 b/dOdds 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/bcTherefore, 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) 150 (a) 80 (b)

Unexposed (no jello) 50 (c) 20 (d)

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.

Analyzing Epi- Curves (4th and 5th Grade)

Outlier: Index Case

Magnitude: 73 cases total

Time Trend: First case on Day 11, peak # of cases on Day 21, no cases after Day 28

Minimum Incubation Period: 7 days

Average Incubation Period: 10 days

Likely Period of Exposure: 3 days

Epi- Curves – Patterns of Disease Spread (4th and 5th Grade)

(one-time exposure) (person-to-person)

Graphs

EXAMPLE of a Bar Graph: (For 2014, the graphs will be related to foodborne illness)

Pertussis Infection by 5-Year Age Groups (www.cdc.gov)

Which age group has the largest number of cases? 0-4True or False: As you grow older, the incidence of pertussis infection decreases (True).

Line GraphsEXAMPLE of a Line graph: www.cdc.gov

How many TB cases were there in the United States in 2001?a. About 10,000b. About 25,000c. About 16,000d. Cannot tell from the FigureAnswer: c

Which of the following statements is false?a. There were more Tuberculosis (TB) cases in

1993 than in 1984.b. For the years shown in the Figure, the year

with the fewest TB cases was 2001.c. For the years shown in the Figure, the only

year when there were fewer than 20,000 TB cases was 1999.

Answer: c

Control and Prevention Strategies

1. 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

2. Aim at chain of agent-source-host – break the chain of transmission at any of its 3 points

3. Interrupt transmission or exposure – isolate vehicles of transmission

4. Reduce susceptibility – with immunization, legal issues and/or education

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.

An example of info needed for a specific food-borne illness:

E. coli (Shiga toxin E. coli infection or STEC infection) http://www.cdc.gov/foodsafety/diseases/

Agent Bacteria ( E. coli), rod shaped, gram negative General info Normally live in the intestines of people and ruminant animals,

(including cattle, goats, sheep, deer, and elk); an important part of a healthy human intestinal tract; Most are harmless but some are pathogens.

Transmission The major source for human illnesses is cattle; Consumption of contaminated food (with human or animal feces), consumption of unpasteurized (raw) milk, consumption of water that has not been disinfected, contact with cattle, or contact with the feces of infected people.

Associated high risk foods

These foods include unpasteurized (raw) milk, unpasteurized apple cider, and soft cheeses made from raw milk.

Unique features

Produces shiga toxin; These bacteria that cause human illness generally does not make animals sick; incubation period of 3-4 days.

People at risk People of any age can become infected; At risk: very young children and the elderly.

(4th and 5th Grade)

An example of info needed for a specific food-borne illness:

E. coli (Shiga toxin E. coli infection or STEC infection) http://www.cdc.gov/foodsafety/diseases/

Symptoms Vary for each person but often include severe stomach cramps, diarrhea (often with blood), vomiting and sometimes fever.

Diagnosis Laboratory test of stool (feces) samples for the presence of Shiga toxins.

Treatment Hydration, antibiotics have not been helpful. Prevention Wash your hands thoroughly after using the bathroom or changing diapers

and before preparing or eating food. Wash your hands after contact with animals or their environments (at farms, petting zoos, fairs, even your own backyard). Cook meats thoroughly. Avoid raw milk, unpasteurized dairy products, and unpasteurized juices (like fresh apple cider). Avoid swallowing water when swimming or playing in lakes, ponds, streams, swimming pools, and backyard “kiddie” pools. Prevent cross contamination in food preparation areas by thoroughly washing hands, counters, cutting boards, and utensils after they touch raw meat.

(4th and 5th Grade)

Useful Links• National Science Olympiad - http://www.soinc.org/disease_detectives_b

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 - http://scioly.org/wiki/index.php/Test_Exchange#Disease_DetectivesAgain, 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 - http://www.cdc.gov/excite/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 - http://www.cdc.gov/foodsafety/index.html, http://www.cdc.gov/foodsafety/diseases/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 - http://www.fammed.ouhsc.edu/tutor/analdes.htm, http://omerad.msu.edu/ebm/Prognosis/Prognosis3.htmlThe emphasis is on being able to identify a given study as either a cohort or a case control.

Fun Links and Questions

Fun Links:http://www.disease-detectives.org/Welcome.htmlhttp://www.pbs.org/wgbh/nova/body/disease-detective.htmlhttp://www.diseasedetectives.org/http://library.thinkquest.org/06aug/01865/

ANY QUESTIONS??

Please email:weso.science@gmail.comSubject: Disease Detectives

HAVE FUN!!