This is a draft cheat sheet. It is a work in progress and is not finished yet.
Epidemiology definitions
morbidity |
state of being diseased |
morbidity rate |
% of diseased individuals in a population |
mortality rate |
% of population that has died of disease |
epidemiology |
study of how diseases originate and how that are passed through communities |
epidemiologists |
must take into account time, place, # of people, frequency of disease when studying diseases. |
incidence |
fraction of a population that contracts a disease during a specific time |
prevalence |
fraction of a population having a specific disease at a given time |
sporadic disease |
disease that occurs occasionally in a population. |
endemic disease |
disease constantly present in a population(cold). |
epidemic disease |
disease acquired by many hosts in a given area in a short time (flu). |
pandemic disease |
world wide epidemic (covid). |
portals of entry
skin |
parasitic worms and fungi |
mucous membranes |
easiest way for pathogens to enter body |
parental route |
pathogens deposited directly into tissues |
development of disease
incubation period |
between infection and first sign and symptom |
prodromal period |
relatively short period with mild and early symptoms |
illness |
disease most severe, patient dies if immune response not sufficient |
decline |
patient vulnerable to second infection at this time. signs and symptoms subside |
convalsecence |
regaining of strength |
|
|
important history
Louis Pateur |
germ theory |
Robert Koch |
cause of disease |
Joseph Lister |
control of disease |
John snow |
mapped cholera in London |
Ignaz Semmelweis |
proved hand washing effective in reducing death during child birth |
Florence Nightingale |
Showed improved sanitation decreased the incidence of epidemic typhus |
patterns of disease
1. source of infection (reservoir |
2. transmission |
3. invasion (pathogenesis) |
transmission of disease
direct contact transmission |
person to person by physical contact |
indirect contact transmission |
reservoir to host by non living object |
droplet contact transmission |
microbes spread in droplet nuclei |
vehicle transmission |
transmission by inanimate reservoir |
mechanical vector transmission (passive) |
vector physically carries disease and drops on host |
biological vector transmission (active) |
spreads microbes through inside vector |
severity of disease
acute disease |
symptoms develop rapidly but last short amt of time |
chronic disease |
disease develops slowly but lasts long time |
subacute disease |
intermediate between acute and chronic |
latent disease |
is dormant but can have active periods |
limit disease transmission
enforcing standards of cleanliness |
work to reduce # of disease vectors and reservoirs |
establish and enforce immunization schedules |
locate and treat individuals exposed to contagious pathogens |
establish isolation and quarantine measures to control the spread of pathogens |
educate public |
|
|
epidemiology data
descriptive |
(who, what, when where) data that describes occurrence of disease |
analytical |
(why) comparison of diseased and healthy |
experimental |
(hypothesis and answer) controlled experiments used to study disease |
koch's postulates
microbes cause specific disease |
bacillus anthracis |
cultured bacteria still infectious |
reservoirs of infection
human reservoirs |
transmit directly or indirectly to others |
animal reservoirs |
direct contact with animal or pet waste, contaminated food and water, consuming infected products |
non living reservoirs |
soil, water if contaminated, food |
virulence measured
ID50/ infectious dose |
how many microbes needed to make 50% of population sick |
LD50/ lethal dose |
how many lethal doses needed to kill 50% of population |
extent of host involve
local infection |
limited small area of body (stays localized) |
systemic infection |
an infection throughout the body |
focal infection |
local infection turned into systemic infection |
HAIs
nosocomial infection or HAIs |
infection acquired in health acre facility |
exogenous |
acquired from health care environment |
endogenous |
normal microbiota become opportunistic because of hospitalization or treatment |
iatrogenic |
"doctor induced". use of catheters and invasive diagnostic procedures, surgery |
|
