Can some one please check this for me. I am not sure if I am on the right track.
Complete the problem below.
Disease X is one that often results in severe illness, but never is fatal. On March 21, 1990, 30 students developed disease X among all students in an introductory epidemiology course at a university. (Assume all epidemiology students were exposed to the index case, the instructor.) Through antibody titers we were able to determine the following:
Using your knowledge of infectious disease epidemiology, quantify the pattern of disease X in this group, i.e., what are the infectivity, pathogenicity, and virulence of disease X?
a.# of exposed students not infected = 40
Not Infected
Number of ill students + # of students not infected = Total Attack rate
30 40 70 43%
b. # of exposed students with sub clinical infection = 10
Sub clinical infection
# of exposed students + # of students not exposed = Total Attack rate
30 10 40 75%
c. # of exposed students with mild symptoms = 10
Mild symptoms
# of exposed students + # of students not expose = Total Attack rate
10 40 50 20%
d. # of exposed students with moderate symptoms = 10
Moderate symptoms
# with moderate symptoms + # without moderate symptoms= Total Attack rate
10 40 50 20%
e. # of exposed students with severe symptoms = 10
Severe symptoms
# exposed with symptoms + # without severe symptoms = Total Attack rate
10 40 50 20%
Thanks
The answer is
It seems like you are working on a problem related to infectious disease epidemiology, specifically about Disease X in a group of students. To answer the questions regarding the pattern of disease X in the group, you need to analyze different indicators, such as infectivity, pathogenicity, and virulence.
Before we proceed, it would be helpful to understand the definitions of these concepts:
1. Infectivity: Refers to the ability of an infectious agent (in this case, Disease X) to invade and establish an infection in a host (the students).
2. Pathogenicity: Refers to the ability of an infectious agent to cause disease in a host.
3. Virulence: Refers to the degree or intensity of the pathogenicity, essentially how severe the disease is once it occurs.
Now, let's go through each part of the problem to determine the specific values for infectivity, pathogenicity, and virulence.
a. The attack rate in this case is the proportion of exposed students who got infected with disease X. From the given information, it states that 30 students developed disease X among all students in the class, and the total number of exposed students is not mentioned. However, it does state that the number of exposed students not infected is 40. To find the total number of exposed students, you need to add the number of exposed students not infected with the number of students who got infected. So, the total exposed students would be 30 (infected) + 40 (not infected) = 70. Thus, the attack rate would be 30/70 = 43%.
b. In this case, you are given the number of exposed students with subclinical (mild or no) symptoms, which is 10. The total number of exposed students is not mentioned directly, but it states that the number of exposed students not exposed is 10. To find the total number of exposed students, you need to add the number of exposed students with subclinical infection to those not exposed. So, the total exposed students would be 30 (exposed) + 10 (not exposed) = 40. The attack rate would be 10/40 = 25%.
c. Similarly, for the number of exposed students with mild symptoms, it is given as 10. The total number of exposed students is not mentioned directly, but it states that the number of exposed students not exposed is 40. Therefore, the total exposed students would be 10 (mild symptoms) + 40 (not exposed) = 50. The attack rate would be 10/50 = 20%.
d. For the number of exposed students with moderate symptoms, it is given as 10. The total number of exposed students is not mentioned directly, but it states that the number of exposed students without moderate symptoms is 40. Therefore, the total exposed students would be 10 (moderate symptoms) + 40 (without moderate symptoms) = 50. The attack rate would be 10/50 = 20%.
e. Finally, for the number of exposed students with severe symptoms, it is given as 10. The total number of exposed students is not mentioned directly, but it states that the number of exposed students without severe symptoms is 40. Therefore, the total exposed students would be 10 (severe symptoms) + 40 (without severe symptoms) = 50. The attack rate would be 10/50 = 20%.
To summarize the findings for infectivity, pathogenicity, and virulence based on the given information:
- Infectivity: The attack rate in this case can be used as a measure of infectivity. It shows how likely exposed students are to get infected, with values ranging between 43% and 75%.
- Pathogenicity: The information doesn't provide specific data on pathogenicity, as it doesn't separate the number of infected students into different categories based on severity.
- Virulence: The attack rates for students with different levels of symptoms (mild, moderate, and severe) are all the same at 20%, suggesting that the disease has a consistent level of severity regardless of symptoms.
Remember, these interpretations are based on the information provided, and further analysis may be required for a more comprehensive understanding. The specific definitions and calculations will depend on the context and parameters of the problem.