PLTW Medical Interventions: Activity 1.4.3 Life of an Epidemiologist

Comprehensive practice flashcards for PLTW Medical Interventions Activity 1.4.3 Life of an Epidemiologist, covering outbreak investigations, food-specific attack rate calculations, study designs (cohort and case-control), historical epidemiology, and professional responsibilities.

In the introductory scenario, where does the team of scientists, doctors, and public health professionals touch down?

Central Africa

What protective gear does the response team verify before stepping out of the helicopter in Central Africa?

They pull respirators over their faces and perform a final check of their protective suits.

Why is even a tiny tear in a protective suit considered disastrous in the Central Africa scenario?

Because it could expose the responder to a lethal hemorrhagic fever virus.

What severe pathology does the hemorrhagic fever virus cause in affected patients in Central Africa?

It leaves bodies writhing in pain and seeping blood as organs and tissue liquefy.

What type of infectious agent is responsible for the hemorrhagic fever outbreak in the introductory scenario?

A tiny virus

What critical mission must the response team accomplish rapidly in Central Africa?

Find the source of the outbreak and prevent further spread.

How does the introductory text define epidemiologists?

Dedicated medical professionals at the heart of the public health field who monitor the health of populations and search for patterns in disease.

What are two distinct types of investigations epidemiologists may conduct according to the introduction?

They may assist in outbreak investigations or examine lifestyle factors and their relationship to chronic illnesses such as heart disease, diabetes, and cancer.

What three work settings are listed for epidemiologists?

In the field, in a lab, or in an office.

Why is the role of an epidemiologist compared to that of a detective?

They investigate health-related matters by gathering information, examining data, and looking for patterns.

What four outcomes does gathering information and examining patterns allow an epidemiologist to achieve?

Define the health issue of concern, determine its cause(s), establish a timeline, and develop solutions, treatments, and preventive measures.

What is the overarching goal of an epidemiologist's work?

To protect public health.

What four key fields of knowledge must an epidemiologist possess?

1. Clinical medicine
2. Pathology
3. Biostatistics
4. Social science

How does the curriculum define biostatistics?

The application of statistical methods to data relating to human biology, health, and medicine.

How does the curriculum define social science?

The study of human behavior and society.

Why must epidemiologists be adept communicators?

To navigate the complexity of medical and scientific concepts and explain them clearly to the general public.

Through which three media or formats do epidemiologists commonly explain concepts to the public?

Interviews, presentations, and written updates.

In Step 1 of Lesson 2, which CDC resource are students directed to visit?

The Centers for Disease Control and Prevention's EXCITE Introduction to Epidemiology resources.

Which four reading sections are assigned from the CDC EXCITE resources in Step 1?

First Incident, Second Incident, Third Incident, and Epidemiology Defined.

What two reflective questions must students answer in their career journal under Step 4 Reflection?

1. What is the most appealing aspect of a career in epidemiology?

2. What would be the most difficult part of being an epidemiologist?

In Step 4, how many possible duties of an epidemiologist must students list in their career journal?

At least ten ($10$) possible duties.

Which specific bacterial infectious disease are students instructed to research in Step 5?

Cholera

What four research questions about cholera must students answer in their laboratory notebook in Step 5?

1. What causes cholera?
2. How is cholera transmitted?
3. What are the symptoms of cholera?
4. What preventive measures have helped eliminate the threat of cholera in the United States?

What is the title of the article assigned in Step 6?

John Snow, Cholera, the Broad Street Pump; Waterborne Diseases Then and Now

Who is considered by many to be the father of epidemiology?

John Snow

In what city and decade did John Snow conduct his famous cholera investigation?

London in the 1850s

What two items regarding John Snow's work must students record in their laboratory notebook in Step 7?

1. The steps Snow took to investigate and stop the spread of cholera in London in the 1850s.
2. The evidence he used to determine the source of the outbreak.

In the Task 1 scenario, what facility is the epidemiologist called to investigate?

A small, rural middle school

How many students reported to the nurse's office in the Task 1 scenario?

Over fifty ($> 50$) students

Over what time period did the middle school students report illness to the nurse?

In the last three ($3$) hours

What specific symptoms did the middle school students complain of?

Nausea and vomiting

What two historical sources of inspiration are students instructed to use when developing questions in Step 9?

Ideas from the John Snow case and their own research.

What must students describe in Step 10 to help solve the school outbreak?

Possible evidence that could be collected to determine whether the cases are connected, identify the source of the infection, and answer their investigative questions.

Based on the middle school students' severe gastrointestinal symptoms, what type of pathogen does the epidemiologist suspect?

A food-borne pathogen

What action does the epidemiologist take to pinpoint the source of the school infection?

Interview the symptomatic students regarding the specific foods they consumed in the school cafeteria.

How is an attack rate defined epidemiologically?

The number of people at risk who develop a certain illness divided by the total number of people at risk.

What is the mathematical formula used to calculate a food-specific attack rate?

What four column headings are present in the Food Survey Results table?

Food, Ill, Well, and Total Attack Rate.

How many total food items are evaluated in the Food Survey Results table?

Seven ($7$) food items: Milk, Banana, Cheese Pizza, Chicken Nuggets, Potato Salad, Chocolate Pudding, and Ice Cream Sandwich.

According to the Food Survey Results table, how many students who consumed Milk became ill, remained well, and what was the total?

Ill: $45$, Well: $24$, Total: $69$

According to the Food Survey Results table, how many students who consumed Banana became ill, remained well, and what was the total?

Ill: $20$, Well: $11$, Total: $31$

According to the Food Survey Results table, how many students who consumed Cheese Pizza became ill, remained well, and what was the total?

Ill: $10$, Well: $48$, Total: $58$

According to the Food Survey Results table, how many students who consumed Chicken Nuggets became ill, remained well, and what was the total?

Ill: $40$, Well: $24$, Total: $64$

According to the Food Survey Results table, how many students who consumed Potato Salad became ill, remained well, and what was the total?

Ill: $43$, Well: $10$, Total: $53$

According to the Food Survey Results table, how many students who consumed Chocolate Pudding became ill, remained well, and what was the total?

Ill: $18$, Well: $10$, Total: $28$

According to the Food Survey Results table, how many students who consumed Ice Cream Sandwich became ill, remained well, and what was the total?

Ill: $36$, Well: $23$, Total: $59$

What is the food-specific attack rate for Milk?

$\frac{45}{69} \approx 65.2\%$ (or $0.652$)

What is the food-specific attack rate for Banana?

$\frac{20}{31} \approx 64.5\%$ (or $0.645$)

What is the food-specific attack rate for Cheese Pizza?

$\frac{10}{58} \approx 17.2\%$ (or $0.172$)

What is the food-specific attack rate for Chicken Nuggets?

$\frac{40}{64} = 62.5\%$ (or $0.625$)

What is the food-specific attack rate for Potato Salad?

$\frac{43}{53} \approx 81.1\%$ (or $0.811$)

What is the food-specific attack rate for Chocolate Pudding?

$\frac{18}{28} \approx 64.3\%$ (or $0.643$)

What is the food-specific attack rate for Ice Cream Sandwich?

$\frac{36}{59} \approx 61.0\%$ (or $0.610$)

Which food item in the survey had the highest attack rate?

Potato Salad with an attack rate of approximately $81.1\%$ ($\frac{43}{53}$).

Which food item in the survey had the lowest attack rate?

Cheese Pizza with an attack rate of approximately $17.2\%$ ($\frac{10}{58}$).

What conclusion can an epidemiologist draw regarding the most probable source of the school food poisoning outbreak?

Potato salad is the most probable source because it has the highest attack rate ($81.1\%$) among all surveyed food items.

What biological or culinary rationale makes Potato Salad a classic suspect in food-borne outbreaks?

It contains mayonnaise, dairy, or eggs that spoil quickly at improper holding temperatures, creating an ideal environment for bacterial pathogens.

What further questions must an epidemiologist investigate to confirm that potato salad caused the outbreak?

Questions regarding preparation methods, refrigeration/storage temperatures, specific ingredients, food handler hygiene, and laboratory testing of food samples and patient stool cultures.

How does the curriculum define an epidemic curve in Step 14?

A graphical distribution of the times of onset of disease.

What critical information does an epidemic curve provide to an outbreak investigation?

It shows the outbreak's magnitude, time trend, pattern of spread (e.g., point source vs. propagated), and helps determine the probable time of exposure.

Why do epidemiologists organize formal studies according to Lesson 5?

To test possible associations between risk factors and disease.

Do all epidemiologists focus on infectious diseases and acute outbreaks?

No; many epidemiologists study factors that contribute to the development of chronic diseases such as cancer and heart disease.

What are the two most common observational study designs utilized by epidemiologists?

The cohort study and the case-control study.

What is the alternative name for a cohort study?

A prospective study

How does an investigator set up and conduct a cohort study?

The investigator selects a group of exposed individuals and a group of nonexposed individuals and follows both groups over time to determine the incidence of disease.

What is the alternative name for a case-control study?

A retrospective study

How does an investigator set up and conduct a case-control study?

A group of individuals with the disease (cases) are identified and compared to a group of people without the disease (controls), and both are surveyed regarding prior exposure to the risk factor.

In a case-control study, who are the 'cases' and who are the 'controls'?

'Cases' are individuals who have the disease; 'controls' are individuals who do not have the disease.

Why must cases and controls be carefully matched on non-exposure criteria in a case-control study?

To prevent confounding variables from distorting the results, ensuring that any differences observed between groups are due to the risk factor being investigated.

What specific patient characteristics are commonly matched between cases and controls?

Age, sex, and underlying medical conditions.

In Step 15, what clinical association are students instructed to investigate using both a case-control and a cohort study design?

The link between smoking and elevated cholesterol levels.

In Step 15, what two elements must students include for both study designs in their career journal?

Information about the participants in the study and a description of how study data would be analyzed.

How would participants be grouped in a cohort study examining smoking and elevated cholesterol?

Select a group of smokers (exposed) and a group of non-smokers (nonexposed) who initially have normal cholesterol levels, and follow them over time to measure cholesterol elevation incidence.

How would participants be grouped in a case-control study examining smoking and elevated cholesterol?

Select individuals with elevated cholesterol (cases) and match them to individuals with normal cholesterol (controls), then survey both groups about their past smoking history.

Which conclusion questions must students answer in Step 16?

Conclusion Questions 2 through 5.

What is the title of Lesson 6 of 7?

Optional Task 4

Under what condition are students instructed to complete Lesson 6 (Optional Task 4)?

Complete this task if directed by your teacher.

Beyond studying disease distribution and influencing factors, what additional responsibilities do epidemiologists have according to Lesson 6?

They evaluate and implement disease prevention, treatment, and health care delivery.

In Step 17, how many diseases must students choose from the provided list?

Two ($2$) diseases

Which nineteen infectious and chronic conditions are listed for selection in Step 17?

Tuberculosis, Hantavirus pulmonary syndrome (HPS), Mad cow disease, Avian influenza (bird flu), Malaria, Lyme disease, Cervical cancer, Legionnaire disease, Plague, Measles, Ebola hemorrhagic fever, AIDS, Smallpox, Polio, Anthrax, West Nile Virus, SARS, and COVID-19.

In Step 19, what must students write for their first chosen disease?

A short paragraph describing prevention efforts, specifying their geographical location and detailing how the action or medication prevents the disease.

In Step 20, what must students write for their second chosen disease?

A short paragraph describing efforts in treating the disease or designing a new therapy, explaining how the treatment stops symptoms or cures the patient.

In Step 21, what additional information must be integrated into the paragraphs for both selected diseases?

Any barriers encountered in delivering health care and completing epidemiologic work unique to each disease situation.

What is the prompt of Conclusion Question 1?

Describe how John Snow’s investigation may have differed if the cholera outbreak occurred today. Think about the interventions and tests you have explored in this lesson.

What is the prompt of Conclusion Question 2?

What are the advantages and disadvantages of studying disease using a cohort study?

What is the prompt of Conclusion Question 3?

What are the advantages and disadvantages of studying disease using a case-control study?

What is the prompt of Conclusion Question 4?

Why is it important to match case subjects and control subjects so closely in a case-control study?

What is the prompt of Conclusion Question 5?

Explain why a case-control study is often referred to as a retrospective study.

What is the prompt of Conclusion Question 6?

Describe at least four ways an epidemiologist could have helped in handling and analyzing the outbreak of hemorrhagic fever in Africa.

What is the prompt of Conclusion Question 7?

How do epidemiologists play a role in the diagnosis, treatment, and prevention of chronic illnesses, such as cancer or heart disease?