Week 12 Flashcards
what are the links in the chain of infection
- infectious microbe
- susceptible host
- reservoir
- portal of exit
- modes of transmission
- portal of entry
infective etiologies
smallest to biggest
- prions
- viruses
- bacteria
- fungi
- protozoa
- multicellular parasites
routes of transmission
- person-to-person
- common vehicle/source
- vector borne
- endogenous
mechanisms of route of transmission
- airborne
- contact with infectious material
direct person to person transmission
- sexual transmission
- perinatal mother to child transmission
- needle injection
- skin-to-skin
- human bites
indirect person to person transmission
- fomites (contaminated objects)
- air: airborne & droplets
common vehicle spread
ingested & biological products
zoonotic agents
animal bites, blood/air/food/water/vector borne
what are endogenous routes of transmission
from human flora
systemic clinical features of infection
- fever
- chills
- constitutional symptoms
local clinical features of infection
site-dependent
pathogenicity
ability to cause disease in the host
virulence
extent of disease caused by organism
walking pneumonia AKA
pneumonia from mycoplasma pneumoniae
pneumococcal pneumonia AKA
pneumonia from streptococcus pneumoniae
mechanism of virulence includes
maintaining presence & invading host
- capsules/cell wall
- toxins
- adhesins
- enzymes
what is the function of capsules/cell wall
evade host defences such as phagocytosis & white cell attachment
what is the virulence function of gram negative bacteria
mediates septic shock using lipopolysaccharide
what is the virulence function of clostridium difficile toxins
causes clostridium difficile associated diarrhea, colitis
what is the virulence function of encapsulated bacteria
capsules help prevent phagocytosis and recognition by host immune system