unit 6 infectious diseases Flashcards
colonization
population established on a host
–> has to be living and multiplying
infection
invasion of cells and tissues by pathogens
acute
rapid onset of symptoms that ends with complete resolution or death
chronic
prolonged + persistent infections that are slow to resolve or never reside
sub-acute diseases
active infection without noticeable symptoms
pathogenesis
process by which infection develops
virulence
pathogens ability to cause damage and the severity of factors that cause damage
carriers
carry disease
reservoirs
where organism is naturally maintained and reproduced
vectors
organism that carries disease causing agent
pathogens vs opportunistic pathogens vs nonpathogens
pathogens: cause infection amongst all
opportunistic: normally commensal, but becomes pathogens
nonpathogens: incapable of causing disease
5 stages of infection
- incubation
- prodromal
- illness
- decline
- convalescence
necessary criteria for sustaining infectious agents within a population
dependent on availability of susceptible individuals and degree of population infection
outbreak
result from introduction of an infectious agent into an area
epidemic
large abrupt outbreaks that occur over a larger population over short period of time
pandemic
continent-wide or worldwide epidemics
typical pathology of viral spread to human host
local infection with nonspecific symptoms –> viremia with systemic symptoms –> infection of secondary tissues –> resolution and latent infection
mechanisms by which viruses are transmitted to humans
fomites (door knob), respiratory (droplets), fecal-oral, direction contact with secretions, parenteral (blood transfusion), transplacental (in utero), vectors (mechanical/biological, zoonoses
factors that help determine severity of viral diseases
pathogenicity (stability, infectious dose, etc.), target tissue, and host defenses and immune status
role of innate immunity in protecting humans against viral infections
direct killing of viral infected cells
HMI in protecting against viral infections
AB act as opsonins or neutralizing Ab’s that prevent attachment to host cells
CMI in protecting against viral infections
CD8 cytotoxic cells kills viral infected cells
viremia
virus to bloodstream
permissive tropism
permissiveness of cells to allow for viral replication (appropriate receptors for virus to attach)
