Epidemiology Flashcards
Epidemiology
The study of the occurrence and distribution and determinants of health related evets, states and processes in specified population
- Includes the study of the detriments influences such processes
- includes the application of these things
What does epidemiology allow us to study?
- The frequency of a disease or a condition
- The distribution of a disease or condition
- Causal factors
What are the questions you need to answer in epidemiology?
- How individuals/populations are affected → clinical signs
- What causes →pathogen, causal factors, etc
- When they are affected → time or life stage
- Who is affected → characteristic of those affected (age, sex, breed, etc)
- Where they are affected → location (where is it concentrated)
Also state prevalence/incidence and mode of transportation
The epidemiological triad of disease
Host
Agent
Environment
sometimes vector
Provide three examples of
Host Factors
Epidemiology
- Age
- Sec
- “Use”
- Genetics
- Immunity (includes vaccination status)
- Medical history
- Ect
Provide three examples of:
Agent Factors
Epidimiology
Biological (bacteria, viruses, yeast, ect)
Chemical (toxins, poison, feed, ect)
Mechanical (physical injury, ect)
Nutritional
Provide three examples of:
Environmental factors
Epidemiology
Geographic location
Climate
Water supply
DOES NOT INCLUDE VACCINATION STATUS
Modes of disease Transmission
Epidemiology
Direct - contact must be made between individuals
- Ex. Sexual interaction (contagious equine metris)
Indirect - Transmission via a common source (ex. Water source)
- Can be a vector or a fomite
Vector - Transmission via a living source
- Diseases is carried by a vector but doesn’t cause disease
- They aren’t sick themselves
NOT THE SAME AS CROSS CONTAMINATION
Ex. Mosquitoes, ticks, fleas
Ex. West Nile, EEE, the plague,
Fomite - Transmission via a non-living source
- Contaminated needles, boots, ect
Are we a vector or a formite?
Is it in you (vector), or is it on you (fomite)
Endemic
Continual source of a pathogen in a limited region
* It’s in the environment
* You can’t really get rid of it
Epidemic
Atypical increased occurrence of an illness in a limited region
- Flu season
Pandemic
Increased occurrence of illness that crosses national borders
Outbreak
Epidemic limited to a localized, rapid increase in the incidence of a disease
* Small amount
* Sudden, rapid
What are the types of outbreaks?
Single point of research - Single point of exposure
* One source of exposure to the pathogen at a single point of time
Multiple exposure - Multiple sources of exposure or different groups are susceptible at different times
* Could be endemic
Continuous exposure - A population (or herd) is exposed to a continuous source of disease
* Sickness all the time
* Could be endemic, epidemic, or pandemic
Measures of Occurence
Epidemiology
Incidence - The number of NEW CASES that occur in a population at risk during a specified period of time
Can account for risk and rate
Prevalence - The number of EXISTING cases in a population at a specific time
Could be a single time point or a long term measure (typically the longer term)
