Unit 9 - Epidemiological Considerations Flashcards
Epidemiology
Branch of medicine studying populations, not individuals. It studies patterns, outbreaks, causes and effects of diseases. Studies occurrence, spread, and control of diseases.
Diseases with longer incubation time are _____ to control
harder
Infection
Presence of an infectious organism in an individual or population
Disease
Detectable clinical consequence of infection
Incubation time
Time interval between exposure to infection and appearance of disease
Infectious
Infected person capable of transmutation infection to others
Transmission
Spread of infection
Symptoms
What the patient feels (ex. pain, malaise, etc). Symptoms are subjective and can change
Sign
Objective and concrete. Can be measured through direct observation
List the 3 Classifications of microbial diseases
1) Communicable
2) Contagious
3) Non-communicable
Define “Communicable” microbial diseases
- Spread from one individual to another
- Direct or indirect spread
Ex. gonorrhoea, chicken pox, measles, mumps
Define “Contagious” microbial diseases
-Easily spread
Ex. chicken pox, measles
Define “Non-communicable” microbial diseases
-Not spread through individuals
Ex. tetanus
Describe time periods of infections
Susceptible
Latent period
Infectious period
Non-infectious period
Describe time period of infectious diseases
Susceptible
Incubation period
Symptomatic period
Non-disease period
What does generation time = ?
latent period + infectious period
List the 4 classifications of microbial diseases
- Endemic disease
- Sporadic
- Epidemic
- Pandemic
Endemic disease
Constant and ongoing disease in a certain geographical region or affecting a certain race/ethnicity
Sporadic diseases
Diseases that occur in the apparent absence of any environmental or inherited cause
Epidemic disease
Occurs when an infectious disease spreads rapidly to many people.
Pandemic disease
global disease outbreak (like an epidemic but affects a much larger group of people, either a whole continent or bigger)
Microbial diseases can either be Acute, Chronic, or Latent:
Describe Acute
Rapidly developing with short duration
ex. influenza
Microbial diseases can either be Acute, Chronic, or Latent:
Describe Chronic
- Usually develop from chronic infections
- Slow to develop with continual duration
ex. tuberculosis
Microbial diseases can either be Acute, Chronic, or Latent:
Describe Latent
latent = silent
- Inactivated for certain periods of time
ex. chicken pox/shingles
List the types of epidemiological studies
1) Cross-sectional studies
2) Case-control study
3) Cohort study
4) Intervention study
Describe cross-sectional studies
ex. HBV
- Outcome and exposure are determined at the same time
Describe a case control study
ex. HPV
- Cases with the outcome and controls without the outcome are identified and their exposure status determined.
Describe a cohort study
ex. HHV + HIV = Kaposi sarcoma
- Individuals with and without the exposure are identified and followed until they develop the outcome or until study end
- Individuals are grouped into exposed and unexposed
Describe an intervention study
-Randomized trials
- Individuals are allocated an intervention and are followed until they develop the outcome of until study end
- Individuals without disease and exposure are allocated an intervention (exposure) at random
Outbreaks can be _____ or _______
local or widespread
Epidemiological studies: ______ not individual
population
Epidemiological studies are ______/_______
observational/interventional
Prevalence
number of existing cases in a population at a given point in time
