Epidemiological Considerations Flashcards
What is epidemiology?
- occurrence, spread and control of diseases
What is an infection?
- presence of an infectious organism in an individual or population
What is a disease?
- detectable clinical consequence of infection
What is incubation time?
- time interval between exposure to infection and appearance of disease
What is considered infectious?
- when an infected people in capable of transmitting an infection onto others
What is infection transmission?
- spread of infection
What is the difference between a sign and a symptom?
- signs are objective and concrete, and can be measured through direct observation
- symptoms are objective and can change based on what the patient feels
What is a communicable disease?
- a disease that is spread easily from one individual to another
- a disease that is spread either directly or indirectly
What are some common examples of communicable diseases?
gonorrhea, chickenpox, measles and mumps
What is considered a contagious disease?
- easily spread– VERY easily spread between people
What is considered a contagious disease?
measles and mumps
What is considered a non-communicable disease?
- tetanus
A shorter incubation period that an infection has the _______
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
What constitutes an endemic?
- 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)
What constitutes an sporadic disease?
- disease is not normally found in the area, these are usually travel related outbreaks (cholera showing up in individuals that have traveled to haiti)
What constitutes an epidemic?
- 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
What constitutes a pandemic?
-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)
What would be considered an acute infection?
- influenza - develops rapidly with a short duration
What would be considered a chronic infection?
- develops from a chronic infection
- slow to develop with continual duration
- ex. tuberculosis
What is considered a latent infection?
- a silent infection that is inactivated for certain periods of time
- considered inactivated for certain periods of time
- chickenpox/shingles
What is a cross sectional study?
- 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
What is a case control study?
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
What is considered a cohort study?
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
What is considered an intervention study?
- 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
