Epidemiological Considerations

Question 1

What is epidemiology?

Answer 1

• occurrence, spread and control of diseases

Question 2

What is an infection?

Answer 2

• presence of an infectious organism in an individual or population

Question 3

What is a disease?

Answer 3

• detectable clinical consequence of infection

Question 4

What is incubation time?

Answer 4

• time interval between exposure to infection and appearance of disease

Question 5

What is considered infectious?

Answer 5

• when an infected people in capable of transmitting an infection onto others

Question 6

What is infection transmission?

Answer 6

• spread of infection

Question 7

What is the difference between a sign and a symptom?

Answer 7

• signs are objective and concrete, and can be measured through direct observation
• symptoms are objective and can change based on what the patient feels

Question 8

What is a communicable disease?

Answer 8

• a disease that is spread easily from one individual to another
• a disease that is spread either directly or indirectly

Question 9

What are some common examples of communicable diseases?

Answer 9

gonorrhea, chickenpox, measles and mumps

Question 10

What is considered a contagious disease?

Answer 10

• easily spread– VERY easily spread between people

Question 11

What is considered a contagious disease?

Answer 11

measles and mumps

Question 12

What is considered a non-communicable disease?

Answer 12

• tetanus

Question 13

A shorter incubation period that an infection has the _______

Answer 13

less time to spread the infection to others - there is a shorter amount of time that the infection goes unnoticed in the person
- you have to get to the CRITICAL NUMBER of organisms before you see the infection being present

Question 14

What constitutes an endemic?

Answer 14

• the disease is prevalent in low levels in certain areas (whooping cough that is only present in low levels of people that do not get vaccinated)

Question 15

What constitutes an sporadic disease?

Answer 15

• disease is not normally found in the area, these are usually travel related outbreaks (cholera showing up in individuals that have traveled to haiti)

Question 16

What constitutes an epidemic?

Answer 16

• a disease where you see much larger numbers of patients in a wide spread area- whooping cough can turn into an epidemic very easily when it is in numbers higher than expected

Question 17

What constitutes a pandemic?

Answer 17

-epidemic that spreads to over 2-3 continents. The disease cases have to be able to originate within that same continent and cannot be travel based (zika for example has to be contracted within both NA and SA)

Question 18

What would be considered an acute infection?

Answer 18

• influenza - develops rapidly with a short duration

Question 19

What would be considered a chronic infection?

Answer 19

• develops from a chronic infection
• slow to develop with continual duration
• ex. tuberculosis

Question 20

What is considered a latent infection?

Answer 20

• a silent infection that is inactivated for certain periods of time
• considered inactivated for certain periods of time
• chickenpox/shingles

Question 21

What is a cross sectional study?

Answer 21

• example HBV
• epidemiological studies are carried out for an entire population - based on this you will design an entire study
• they measure the frequency of an outcome/exposure in a defined population at a particular point in time
• these can be descriptive or analytical, measuring the burden or the frequency of the disease

Question 22

What is a case control study?

Answer 22

They identify people with the outcome, as well as other people without the outcome

• cases and controls are then compared with regards to differences in their past exposure
• these are always analytical studies that ask the question = if the exposure was the thing that caused the disease

Question 23

What is considered a cohort study?

Answer 23

cohort studies follow a group of people that do not initially have the outcome of interest and determine whether they develop the disease

• for example, can monitor people that were born of vaginal birth vs c section and monitor them over such a long period of time
• usually use a very large number of subjects to overcome other factors involved

Question 24

What is considered an intervention study?

Answer 24

• disease free and exposure free individuals are allocated an exposure (intervention) or no exposure (no intervention)
• the two groups are then followed over a long period of time to determine the outcome compared between the two groups
• the intervention is always allocated at random