Principles of Pathogenesis 2 Flashcards
describe the stages of acute infection
exposure
incubation phase: period from exposure till first symptom
prodrome: having symptoms but cannot pinpoint what the problem is – low level symptom
peak of acute phase symptoms: most severe symptom
convalescence: immune system kicks in and severity of symptom goes down
difference between acute and chronic infection
chronic has longer incubation phase and prodrome and also severity of symptoms stay at a constant low level because for some reason immune system cannot clear it out
terminology for chronic infections
chronic
latent - microorganisms is present and not replicating at a high level or not replicating at all
persistent - not being cleared, not being eradicated from the body
carrier - individual’s is persistently shedding microorganism and can be harmful to someone else
compare the two infection types chronic and acute for the following: growth rates of pathogen, symptom onset speed, duration of symptoms, risk to others of infection, advantages to pathogen
chronic - slower, slower, longer but less severe, yes, there are advantages and disadvantages
acute - faster, faster, shorter, yes, there are advantages and disadvantages
define pathogenicity and virulence
pathogenicity is the ability to cause damage and virulence is how we measure that ability
fact about virulence
virulence can be different depending on who it is or can even vary where in the body it is
key to pathogen success
it recognizes in its environment, communicates it, then responds to it
how does pathogen respond to environmental signal
it has a receptor (membrane protein) on itself that receives signal from environmental changes then sends signal to response regulator –> genes –> mRNA –> protein and enzyme released which helps with appropriate adaptation to the environment
the ability to cause damage
virulent
what is pathogenicity islands (PAIs)
cluster of genes encoding for virulence factors
what is the role of clustering genes together
you can control them with the same switch
what is the difference between exogenous and endogenous in term of exposure and entry
exogenous - externally acquired
endogenous - home grown
what does it mean by you can get a cross over between exogenous and endogenous exposure and entry
your endogenous infection can become transmitted to someone else and become a exogenous infection to the other individual
vibrio cholerae in water has 10^4 - 10^6 infectious dose while vibrio cholerae in food has 10^2 - 10^4 infectious dose. Why is the infectious dose lower for V. cholerae when it is in food compared to in water?
probably because of heat from cooking but the levels in the water can be brought down to the levels in food if sodium bicarbonate is added to the water
Food and Sodium Bicarb help protect the virus from stomach acid.
If the virus was in just water, then many of the virions would be destroyed prior to getting to their site of infection.
But taken with food, a greater percentage of virions reach the site of infection so you need fewer in the infectious dose.
what is so important about the site of entry in which a microorganism gets in
same way they get in, is the same way they shed
what are some specialized adhesion structures and when do microorganisms express them
pili and fimbrae
expressed when it is beneficial for them - depending on the environmental conditions
what helps define tissue specificity
tissue tropism
specific adhesion
biofilm formation
what is streptococcus mutans’ bacterial adhesin and attachment site
bacterial adhesin - cell bound protein
attachment site - pellicle of tooth
what is Enterotoxigenic E. coli’s bacterial adhesin and attachment site
bacterial adhesin - Type I fimbriae
attachment site - Intestinal epithelium