pathology
study of disease
etiology
cause of disease
pathogenesis
development of disease
infection
invasion of the body by pathogens
disease
abnormal state in which the body is not performing normal functions
normal microbiota
permanent colonize host, do not cause disease (under normal conditions)
transit microbiota
present for days, weeks or months
microbial antagonism (competitive exclusions)
competition between microbes
normal microbiota protect the host by
competing for nutrients
producing substances harmful for invading microbes
affecting pH and available oxygen
symbiosis
relationship between normal microbiota and host
commensalism
one organism benefits, and the other is unaffected
mutalism
both organisms benefit
paratism
one organism benefits at the expense of others
incidence
# of people who develop a disease during a time period
prevalence
# of people who develop or have a disease at a specified time, regardless of when it first occurred
takes into account both old and new cases)
sporadic disease
occurs only occasionally
endemic disease
constantly present in population
epidemic disease
acquired by many people in a given area in a short time
pandemic
worldwide epidemic
acute disease
symptoms develop rapidly but lasts a short time
chronic disease
symptoms develop slowly
subacute disease
intermediate between acute and chronic disease
latent disease
causative agent is inactive for a time but then activates and produces symptoms
herd immunity
immunity in most of a population
what is a R° value
how many people the average person infects
5 stages of development of disease
incubation disease
prodromal disease
period of illness
period of decline
period of convalescence
incubation period
initial infection
first signs and symptoms
prodromal period
pre-symptomatic
infectious
period of illness
when the disease is more severe
period of decline
signs and symptoms will decline
what is exception when period of illness does not lead to period of decline
death
period of convalescence
body returns to its predeceased state
human reservoirs
carriers: inapparent infections/ latent diseases
animal reservoirs
zoonoses: diseases transmitted from animals to humans
give two examples of non-living reservoirs
soil and water
contact transmission is…
human to human
direct contact transmission
close association of infected → susceptible host
congenital transmission
mother → fetus or newborn at birth
indirect contact transmission
spreads to a host by a nonliving object called a fomite
droplet transmission
transmission via airborne droplets
less than 2 meters
vehicle transmission is…
environment to human
what are three examples of vehicle transmission
airborne
waterborne
foodborne
ID 50
infectious dose for 50% of a sample population, measures virulence of a microbe
vectors
examples, anthropods, fleas, ticks, mosquitoes
transmit disease by two methods… mechanical and biological
mechanical transmission
arthropod carries pathogen on its feet
biological transmission
pathogen reproduces in the vector, transmitted via bites or feces
healthcare associated infections are…
and also known as…
acquired while receiving treatment in a health care in facility
nosocomial infections
what are two types of universal precautions
standard precautions
transmission-based precautions
what are three types of transmission based precautions (give examples)
contact precautions (e.g. gloves and frequent sanitation)
droplet precautions (e.g. masks)
airborne precautions (e.g. ventilation)
epidemiology
study of where and when diseases occur and how they are transmitted in populations
notable infectious disease
physicians are required to report occurrence
morbidity rate (incidence)
# people affected in relation to total population in given time
mortality rate
# of deaths in relation to population in a given time
incidence= (math)
# affected / total population
mortality= (math)
# deaths / # affected