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Epi basic concepts
Epi basic concepts and measures
Question | Answer |
---|---|
What are pathogens characterized by? | Ability to infect, severity of disease, ability to cause death |
Define a foodborne case. | One person having illness after eating a food. |
Define a foodborne outbreak. | A group of people having a similar illness after eating a food, in excess of what is normally expected. |
What are the key steps in an outbreak investigation? | - Detect and validate outbreak existence - Understand the outbreak: distribution and associations/ combinations - Develop and test hypotheses - Make recommendations to control the outbreak |
Define virulence/pathogenicity. | Capacity of a pathogen to cause disease. |
What factors determine pathogenicity? | Nature of pathogenic agent or pathogen, amount of exposure, characteristics of the person who is exposed. |
Define incubation period. | Time between exposure (e.g. eating contaminated food) and appearance of symptoms or clinical disease. |
Define infectious dose. | Number of pathogen cells needed to be ingested to cause illness. |
Define pathogen. | Microorganisms that cause disease. |
Define foodborne illness. | Diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. |
What is a measure of "risk"? | Proportion of unaffected individuals who eventually develop the outcome of interest. it is the probably of disease. |
What is an attack rate? how is it calculated? | It is the risk of getting sick from a specific exposure. Number of cases or sick people among those exposed divided by Total number of people exposed or infected |
What is prevalence? | Number of existing cases in the population either at a certain point in time (= point prevalence) or during a period of time (period prevalence) |
Define an incidence rate. | Development of new cases over time; it is expressed in person-time and takes into account the length of observation or follow-up for each person eligible |
True or false? When persons are no longer at risk, they cannot be included in the denominator when calculating person-time. | True |
Who was the father of epidemiology and what did do? | John Snow; he investigated a cholera outbreak in London in 1854 and implemented the first experimental study (intervention = shutting down Broad Street water pump) |
What factors/ elements make up the disease triad? | Host, agent, environment (and sometimes vector/ vehicle) |
What is epidemiology? | The study of the distribution and determinants of health-related events in specified populations and its application to control health problems |
Why do we use age-standardized mortality rates? | To make relevant comparisons in risks of mortality, that account for differences due to age |