Disease Detectives B/C

[Knyte_Xjn]

What's the difference between incidence and prevalence?

Attempt (Click to Show Hidden Text)

Whereas incidence is the rate of new cases that develop in a population at risk over a period of time (new cases/total population at risk), prevalence is a measure of the percentage of the population afflicted with a specific health state at a given time or throughout a period (point prevalence / period prevalence).

[UTF-8 U+6211 U+662F]

What's the difference between incidence and prevalence?

Attempt (Click to Show Hidden Text)

Whereas incidence is the rate of new cases that develop in a population at risk over a period of time (new cases/total population at risk), prevalence is a measure of the percentage of the population afflicted with a specific health state at a given time or throughout a period (point prevalence / period prevalence).

Yep, your turn

[Knyte_Xjn]

What's the difference between incidence and prevalence?

Attempt (Click to Show Hidden Text)

Whereas incidence is the rate of new cases that develop in a population at risk over a period of time (new cases/total population at risk), prevalence is a measure of the percentage of the population afflicted with a specific health state at a given time or throughout a period (point prevalence / period prevalence).

Yep, your turn

Here are a few relatively basic questions:

1. What is the name of the list of criteria used to determine the existence of a causal relationship?

For the following questions, identify which criterion best matches the description in Part A.
2. a) People who smoke more are at greater risk of contracting chronic obstructive pulmonary disease (COPD).
b) In some cases, this criterion does not hold true. What is observed instead?

3. a) At a seafood restaurant, after 100 people are served raw shellfish, 95% of them contract acute gastroenteritis.
b) Which pathogen likely caused this?
c) Would this spread of disease be best defined as a pandemic, epidemic, endemic, outbreak, or cluster? Explain.

[Tailsfan101]

Here are a few relatively basic questions:

1. What is the name of the list of criteria used to determine the existence of a causal relationship?

For the following questions, identify which criterion best matches the description in Part A.
2. a) People who smoke more are at greater risk of contracting chronic obstructive pulmonary disease (COPD).
b) In some cases, this criterion does not hold true. What is observed instead?

3. a) At a seafood restaurant, after 100 people are served raw shellfish, 95% of them contract acute gastroenteritis.
b) Which pathogen likely caused this?
c) Would this spread of disease be best defined as a pandemic, epidemic, endemic, outbreak, or cluster? Explain.

Click to Show Answer

1. Bradford-Hill criteria



2. a) Biological gradient

b) If you want another criterion, coherence



3. a) Specificity

b) Vibrio vulnificus?

c) Outbreak, because the exposure affects only a small number of people, yet is still significantly more than what is expected

[Knyte_Xjn]

Here are a few relatively basic questions:

1. What is the name of the list of criteria used to determine the existence of a causal relationship?

For the following questions, identify which criterion best matches the description in Part A.
2. a) People who smoke more are at greater risk of contracting chronic obstructive pulmonary disease (COPD).
b) In some cases, this criterion does not hold true. What is observed instead?

3. a) At a seafood restaurant, after 100 people are served raw shellfish, 95% of them contract acute gastroenteritis.
b) Which pathogen likely caused this?
c) Would this spread of disease be best defined as a pandemic, epidemic, endemic, outbreak, or cluster? Explain.

Click to Show Answer

1. Bradford-Hill criteria



2. a) Biological gradient

b) If you want another criterion, coherence



3. a) Specificity

b) Vibrio vulnificus?

c) Outbreak, because the exposure affects only a small number of people, yet is still significantly more than what is expected

1. Correct

2. a) Yep
b) This isn't exactly what I meant by "what is observed instead?" Sometimes, rather than increased exposure leading to increased incidence, an inverse relationship holds true in that increased exposure leads to decreased incidence, and in other cases, a minimal threshold of exposure is sufficient to trigger an effect, so increased exposure does not lead to increased incidence.

3. a) I can see what you were thinking here, but I think temporality suits this scenario better; the key word is 'after', establishing a time-order sequence. Specificity would imply that there is no other likely explanation for the unexpected increase in acute gastroenteritis cases, but given that it's a restaurant, the 95 people who were afflicted may have eaten another food that caused the health effect.
b) Correct
c) Correct; this outbreak would be best classified as a point-source outbreak. Your turn!

[Tailsfan101]

1. What are the five steps of surveillance?
2. What are the four types of surveillance?
3. Give three reasons why surveillance is of benefit to the community.

[Knyte_Xjn]

1. What are the five steps of surveillance?
2. What are the four types of surveillance?
3. Give three reasons why surveillance is of benefit to the community.

Attempt (Click to Show Hidden Text)

1. (1) reporting (2) data accumulation (3) data analysis (4) judgment (5) action 

2. (1) medical surveillance (2) sentinel surveillance (3) passive surveillance (4) active surveillance 

3. (1) measuring the need for interventions in the context of disease outbreak (e.g. isolating lab-confirmed cases and quarantining those who came into contact with them) 
(2) measuring the effects of interventions 
(3) gathering information about diseases and other health effects, especially in regard to how they spread

[Tailsfan101]

1. What are the five steps of surveillance?
2. What are the four types of surveillance?
3. Give three reasons why surveillance is of benefit to the community.

Attempt (Click to Show Hidden Text)

1. (1) reporting (2) data accumulation (3) data analysis (4) judgment (5) action 

2. (1) medical surveillance (2) sentinel surveillance (3) passive surveillance (4) active surveillance 

3. (1) measuring the need for interventions in the context of disease outbreak (e.g. isolating lab-confirmed cases and quarantining those who came into contact with them) 
(2) measuring the effects of interventions 
(3) gathering information about diseases and other health effects, especially in regard to how they spread

All correct, your turn!

[Knyte_Xjn]

1. What are the five steps of surveillance?
2. What are the four types of surveillance?
3. Give three reasons why surveillance is of benefit to the community.

Attempt (Click to Show Hidden Text)

1. (1) reporting (2) data accumulation (3) data analysis (4) judgment (5) action 

2. (1) medical surveillance (2) sentinel surveillance (3) passive surveillance (4) active surveillance 

3. (1) measuring the need for interventions in the context of disease outbreak (e.g. isolating lab-confirmed cases and quarantining those who came into contact with them) 
(2) measuring the effects of interventions 
(3) gathering information about diseases and other health effects, especially in regard to how they spread

All correct, your turn!

Sorry for the late response!
When investigating an outbreak of a food-borne illness what demographics from the population being studied may be useful?
If you are conducting a survey, what questions should you ask the lab-confirmed cases?
Which biases may be introduced as a result of asking these questions, and how can their presence/effects be mitigated?

[UTF-8 U+6211 U+662F]

Attempt (Click to Show Hidden Text)

1. (1) reporting (2) data accumulation (3) data analysis (4) judgment (5) action 

2. (1) medical surveillance (2) sentinel surveillance (3) passive surveillance (4) active surveillance 

3. (1) measuring the need for interventions in the context of disease outbreak (e.g. isolating lab-confirmed cases and quarantining those who came into contact with them) 
(2) measuring the effects of interventions 
(3) gathering information about diseases and other health effects, especially in regard to how they spread

All correct, your turn!

Sorry for the late response!
When investigating an outbreak of a food-borne illness what demographics from the population being studied may be useful?
If you are conducting a survey, what questions should you ask the lab-confirmed cases?
Which biases may be introduced as a result of asking these questions, and how can their presence/effects be mitigated?

Click to Show Answer

1) Age, sex, etc.

2) Assuming a food-borne illness, where they ate, when symptoms started, what they recall eating, etc.

3) Response bias, interviewer bias, and recall bias may occur. Their presence may be mitigated by making sure all questions are partially worded and do not lead the participant.