Disease Detectives B/C

[EwwPhysics]

83 people go to a party. A few days after the party, 35 of the attendees develop Salmonella. Of the 35 ill, 29 ate the hors d'oeuvres, and 11 of the 48 well ate the hors d'oeuvres.
1. Calculate the relative risk for this scenario.
2. Interpret the answer for #1.

1.

Click to Show Answer

5.2

2.

Click to Show Answer

People who ate the hors d'oeuvres were 5.2 times more likely to develop Salmonella than those who didn't.

[Tailsfan101]

83 people go to a party. A few days after the party, 35 of the attendees develop Salmonella. Of the 35 ill, 29 ate the hors d'oeuvres, and 11 of the 48 well ate the hors d'oeuvres.
1. Calculate the relative risk for this scenario.
2. Interpret the answer for #1.

1.

Click to Show Answer

5.2

2.

Click to Show Answer

People who ate the hors d'oeuvres were 5.2 times more likely to develop Salmonella than those who didn't.

Both correct! Your turn.

[vye904]

1. What is it called when a potentially infectious agent is present in a host but has not yet invaded the tissue?
2. Define and explain the difference between a systematic infection and a local infection.
3. There is an outbreak of conjunctivitis at a high school with a population of 400 students. 4 of these students were originally diagnosed with conjunctivitis. In total, the 4 students came in contact with 38 other students and faculty members. One incubation period later, 5 of the contacts were identified with conjunctivitis. Calculate the secondary attack rate for conjunctivitis in this outbreak.

[Pickles]

Explain the characteristics of an agent
• Infectivity
• Pathogenicity
• Virulence

Infectivity - ability to be transmitted and infect the host Pathogenicity - ability to cause disease in a host Virulence - the ability to cause severe disease or death

[Pickles]

Epidemic vs Outbreak

1. 10 cases of polio were reported in the U.S. in 2030 Epidemic 2. 50 people in a public school were infected with a disease Outbreak 3. There were 15 cases in the city park Outbreak 4. There was a 15% increase in botulism cases in New York Epidemic 5. There was a 20% increase in measle cases in the U.S. Epidemic

[Pickles]

1. What is it called when a potentially infectious agent is present in a host but has not yet invaded the tissue?
2. Define and explain the difference between a systematic infection and a local infection.
3. There is an outbreak of conjunctivitis at a high school with a population of 400 students. 4 of these students were originally diagnosed with conjunctivitis. In total, the 4 students came in contact with 38 other students and faculty members. One incubation period later, 5 of the contacts were identified with conjunctivitis. Calculate the secondary attack rate for conjunctivitis in this outbreak.
1. Infection
2. A systematic infection affects the entire body while a local infection does not spread and is confined confined to one organ system or general area in the body.
3. 0.13

[drcubbin]

One factor leading to the emergence of infectious diseases is population growth. Name 5 other factors.

Speed of travel
Global climate changes
War and social disruptions
Increase antibiotics use in both human and animals
Dam building
Human and animal contact

[vye904]

1. What is it called when a potentially infectious agent is present in a host but has not yet invaded the tissue?
2. Define and explain the difference between a systematic infection and a local infection.
3. There is an outbreak of conjunctivitis at a high school with a population of 400 students. 4 of these students were originally diagnosed with conjunctivitis. In total, the 4 students came in contact with 38 other students and faculty members. One incubation period later, 5 of the contacts were identified with conjunctivitis. Calculate the secondary attack rate for conjunctivitis in this outbreak.
1. Infection
2. A systematic infection affects the entire body while a local infection does not spread and is confined confined to one organ system or general area in the body.
3. 0.13

I was looking for "contamination" in question 1. An infection would indicate the agent has already invaded the tissue.

2 is correct, keep in mind a systematic infection is also defined by being in the blood stream.

3 is correct!

New set of questions:

1. What does R0 stand for? Define R0.
2. If a disease has an R0 of 3, what is the approximate percent of a population that needs to be vaccinated to obtain herd immunity?
3. If public health officials have estimated 80-90% of the population needs to be vaccinated in order to obtain herd immunity, what is the disease’s range of possible R0’s?

[Pickles]

1. What is it called when a potentially infectious agent is present in a host but has not yet invaded the tissue?
2. Define and explain the difference between a systematic infection and a local infection.
3. There is an outbreak of conjunctivitis at a high school with a population of 400 students. 4 of these students were originally diagnosed with conjunctivitis. In total, the 4 students came in contact with 38 other students and faculty members. One incubation period later, 5 of the contacts were identified with conjunctivitis. Calculate the secondary attack rate for conjunctivitis in this outbreak.
1. Infection
2. A systematic infection affects the entire body while a local infection does not spread and is confined confined to one organ system or general area in the body.
3. 0.13 [/quote]

I was looking for "contamination" in question 1. An infection would indicate the agent has already invaded the tissue.

2 is correct, keep in mind a systematic infection is also defined by being in the blood stream.

3 is correct!

New set of questions:

1. What does R0 stand for? Define R0.
2. If a disease has an R0 of 3, what is the approximate percent of a population that needs to be vaccinated to obtain herd immunity?
3. If public health officials have estimated 80-90% of the population needs to be vaccinated in order to obtain herd immunity, what is the disease’s range of possible R0’s?
[/quote]
1. RO stands for reproduction number and it is the number of people infected from one infected person.
2. 66.6%
3. Possible RO’s: 5-10

[vye904]

1. What does R0 stand for? Define R0.
2. If a disease has an R0 of 3, what is the approximate percent of a population that needs to be vaccinated to obtain herd immunity?
3. If public health officials have estimated 80-90% of the population needs to be vaccinated in order to obtain herd immunity, what is the disease’s range of possible R0’s?
1. RO stands for reproduction number and it is the number of people infected from one infected person.
2. 66.6%
3. Possible RO’s: 5-10

All correct, your turn!