Epidemiology Flashcards
(35 cards)
Outline Kocks postulates.
To cause disease pathogens must:
Found in all cases of disease
Prepared and maintained in pure culture
Capable of producing the original infection after several generations of culture
Retrievable from an infected animal and able to be cultured again
Who first suggested that some diseases were caused by microorganisms?
Louis Pasteur
What was Rudolph Virchows famous quote about One Health?
Between animal and human medicine there is no dividing line… And nor should there be.
Describe the Anti-Germ theory.
Epidemics are of social origin - use politics to combat
Disease agents used bodies as habitats (didn’t cause disease)
Social change could be used to combat disease
Why is Roisin great?
Because she’s lovely, kind, pretty, smiley, funny and I (Nicole) am very lucky to have such an ace friend!
Association
Reverse causation
Eradication of Rinderpest.
2011
What problems are there with “cause = infectious agent” ?
Multi causal disease:
Infectious agent
Environmental factors - husbandry, stress
Immunological factors
It is important to control the infectious agent and the other factors which are affecting welfare
Outline Hill-Evans postulates.
Vague points, not all need to be fulfilled ***add
Confounder
A third variable which affects both cause and outcome and therefore can distort results.
Structural violence
Exerted by society
What effect does increased sample size have on random error and selection bias?
Random error decreases
Selection bias does not change
Risk
The chance of encountering some form of harm, loss or damage.
Remember, chance = probability, harm, loss or damage = consequence
Outline the basic framework for reducing risk.
Risk analysis - risk management - risk communication
Why should we use risk assessment?
Structures decision making - evidence based, allows us to identify gaps in data.
Useful in context with HACCP - identify hazards
International trade - common understanding of food safety
How does the OIE framework for risk assessment work? (x4 and brief description)
Hazard identification - identify pathogens potentially present in animals.
Release assessment - what is the prob that the agent will be introduced to the given environment?
Exposure assessment - probability that native animals are exposed to agent.
Consequence assessment - consequences if exposure, probability of occurrence
How does the CODEX framework for risk assessment work?
Hazard identification - hazard characterization - exposure assessment - risk characterization
Focus specifically on food-borne risks from microbial hazards
CODEX model
Assessing necessity of regulatory controls and their associated impact
OIE
Emphasis on assessing risks actually present in a given situation
Hazard
The identification of biological, chemical and physical agents capable of causing adverse health effects and which may be present in particular food groups (CODEX)
Exposure assessment
Models used to assess the likelihood of exposure of the population to the agent. Flow charts are useful.
Can be characterised qualitative (red, orange, green) or quantitatively spending on data available or need.
Quantitative risk assessment
Numerical probabilities are given for each stage of a risk assessment model
Risk characterization
Integration of hazard identification, characterization and exposure to obtain a risk estimate
Compare uncertainty and variability.
Uncertainty can be reduced by collecting more data whereas variability requires us to estimate more precisely
