midterm 1 Flashcards
(67 cards)
Who is Hippocrates?
father of medicine, FIRST EPIDEMIOLOGIST
He observed occurence and associated factors.
Who is Thomas Sydenham?
the first to identify and classify diseases based on manifestations rather than using Hippocratic approaches
Who is Ignaz Semmelweis?
Studied puerperal fever (childbed fever). found that if physicians wash hands after autopsy, maternal mortality dec.
Who is John Graunt?
introduced systematic methods for describing disease occurence and death
developed life expectancies and life tables.
EVALUATED BILLS OF MORTALITY (the weekly mortality statistics in london)TO IDENTIFY TREND IN DEATH
Who is William Farr?
one of the first demographers
helped design and analyze london census. SIGNIFICANT ROLE IN VITAL STATISTICS SYSTEM IN LONDON.
****founder of MODERN epi who applied vital statistics to epi problems.
Who is John Snow?
father of FIELD epidemiology. Showed link between high mortality due to cholera and water companies.
Developed and used Spot maps (geographical distribution of deaths)
what is epidemiology?
study of distribution and determinants of health related states and events in populations and the application of this study to control health problems.
distribution and determinants taken together refer to frequency, pattern, factors related to occurence of health events
endemic
occurring at or near the USUAL rate of occurrence
Epidemic
occurence in clear EXCESS of normalcy
Pandemic
an epidemic that affects several countries/ continents
what is the working assumption of disease occurence?
disease does not occur randomly but is a function of disease and population
what does the epidemic triad consist of?
agent, environment and host.
- sometimes time is included as fourth agent. Interaction between triad can result in disease.
- removing one factor can impede disease transmission
what is a reservoir?
is an organism or environment where the agent resides or is harbored
Inapparent carriers
never manifest disease but can transmit (ex: poliomyelitis)
incubatory carriers
will eventually manifest disease and can transmit (ex: measles and HIV)
convalescent carriers
remain infectious even after recovering from illness (ex: salmonella)
infectivity
the ability of a pathogen to establish an infection
pathogenicity
ability of an organism to CAUSE disease (harm the host)
virulence
Harmful quality possessed by microorganisms that can cause diseases
qualitative
determined by virulence factors
quantitative
degree of damage caused by a microbe to its host
what is herd immunity?
the resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune.
**100 % individual immunity is not required to achieve community level (herd) immunity
what are the requirements for herd immunity?
1) disease must be restricted to a single host species
2) prior infections provide full immunity
3) random mixing occurs
factors that determine optimal level of herd immunity (ex: percentage immune required for herd immunity)
1) level in infectiousness (the greater the infectiousness the greater the percentage required)
2) population density (the greater the density, the greater the percentage required)