Disease Detectives B/C

[Unome]

Question (Click to Show Hidden Text)

For each of the three major types of epi curves, give one characteristic of its histogram, and one characteristic of the outbreak itself that could cause that type of curve.

Answer (Click to Show Hidden Text)

Common Source: A single, one-time exposure results in a single peak. Food-borne illness from a convention is one example.

Continuous: A constant exposure results in a plateau of cases. The 1854 London Cholera outbreak is one example.

Propagated: A host serves as a source of exposure for other susceptible hosts, resulting in a serious of growing peaks. A flu pandemic in which no one is initially immune would be one example.

Correct, your turn.

[yang573]

A bit late (Click to Show Hidden Text)

A Minnesota health department enrolled 3,000 (healthy) individuals for 5 years to estimate the incidence rate of Hepatitis C in the Twin Cities metropolitan area. These people were called up annually, and the results are as follow:

After the 1st year, 2 individuals had a new diagnosis for hepatitis C, and 78 were lost to follow up
After the 2nd year, 0 individuals had been newly diagnosed with hepatitis C, and 90 were lost to follow up.
After the 3rd year, 5 individuals had been newly diagnosed with hepatitis C, and 155 were lost to follow up.
After the 4th year, 3 individuals had been newly diagnosed with hepatitis C, and 117 were lost to follow up.
After the 5th year, 6 individuals had been newly diagnosed with hepatitis C, and 49 were lost to follow up.

Calculate the incidence rate (in 1,000 person-years). Assume those lost to follow-up were disease-free for only half of the year.

[Unome]

A bit late (Click to Show Hidden Text)

A Minnesota health department enrolled 3,000 (healthy) individuals for 5 years to estimate the incidence rate of Hepatitis C in the Twin Cities metropolitan area. These people were called up annually, and the results are as follow:

After the 1st year, 2 individuals had a new diagnosis for hepatitis C, and 78 were lost to follow up
After the 2nd year, 0 individuals had been newly diagnosed with hepatitis C, and 90 were lost to follow up.
After the 3rd year, 5 individuals had been newly diagnosed with hepatitis C, and 155 were lost to follow up.
After the 4th year, 3 individuals had been newly diagnosed with hepatitis C, and 117 were lost to follow up.
After the 5th year, 6 individuals had been newly diagnosed with hepatitis C, and 49 were lost to follow up.

Calculate the incidence rate (in 1,000 person-years). Assume those lost to follow-up were disease-free for only half of the year.

Time for me to start studying for this event again... (Click to Show Hidden Text)

Assuming I'm just suppose to halve the number lost to follow up and add it on: 0.0521

[yang573]

Time for me to start studying for this event again... (Click to Show Hidden Text)

Assuming I'm just suppose to halve the number lost to follow up and add it on: 0.0521

Hm, may I see your work? I got a different answer of 1.17 cases per 1,000 person-years. This is the source I used: https://www.cdc.gov/ophss/csels/dsepd/s ... tion2.html

[Alex-RCHS]

Time for me to start studying for this event again... (Click to Show Hidden Text)

Assuming I'm just suppose to halve the number lost to follow up and add it on: 0.0521

Hm, may I see your work? I got a different answer of 1.17 cases per 1,000 person-years. This is the source I used: https://www.cdc.gov/ophss/csels/dsepd/s ... tion2.html

I also got that answer. I added it up and ended up doing:

answer (Click to Show Hidden Text)

16 new cases in 13710 person-years for an incidence of 1.167 cases per 1000 person-years.

[Unome]

Time for me to start studying for this event again... (Click to Show Hidden Text)

Assuming I'm just suppose to halve the number lost to follow up and add it on: 0.0521

Hm, may I see your work? I got a different answer of 1.17 cases per 1,000 person-years. This is the source I used: https://www.cdc.gov/ophss/csels/dsepd/s ... tion2.html

I also got that answer. I added it up and ended up doing:

answer (Click to Show Hidden Text)

16 new cases in 13710 person-years for an incidence of 1.167 cases per 1000 person-years.

Ok, that makes a lot more sense. I had no idea what you meant by "assume those lost to follow-up are disease free for half of the year;" apparently I didn't need that?

[yang573]

Ok, that makes a lot more sense. I had no idea what you meant by "assume those lost to follow-up are disease free for half of the year;" apparently I didn't need that?

You still have to count them toward the person-years observed. I ended up with 13717.5 person-years. Ignoring them here just doesn't have much of an impact due to the number of participants. Feel free to PM me if you have anymore questions.

Your turn to pose a problem.

[Tailsfan101]

The three types of disease transportation are _______borne, ___borne, and ______borne.

[The48thYoshi]

The three types of disease transportation are _______borne, ___borne, and ______borne.

I'm assuming you're referring to only indirect transmissions (Click to Show Hidden Text)

Airborne, Vehicleborne, Vectorborne

[Tailsfan101]

The three types of disease transportation are _______borne, ___borne, and ______borne.

I'm assuming you're referring to only indirect transmissions (Click to Show Hidden Text)

Airborne, Vehicleborne, Vectorborne

Correct! Your turn.