TERM 1
Mathematically
DEFINITION 1
Infectious Disease = No, of Organisms x Virulence Host
ResistanceHost Resistance Factors:
Diet, stress (risk factors)
Age, genetics, vaccination etc
TERM 2
Innate Resistance
DEFINITION 2
Natural host resistance - variable
Physical and chemical defences - provide resistance
Tissue specificity - must adhere to site which is
compatible for adhesion
TERM 3
Paths of Entry
DEFINITION 3
Ingress - entry without crossing
barriersinhalationingestionsexual contactPenetration -
entry by crossing epitheliainsect bitescuts and
woundsblood transfusion / sexual contact
TERM 4
Minimal Infective Dose (MID)
DEFINITION 4
Measure of infectivity - based on the number of microbes
initiating disease.The less needed to cause disease - great
the infectivity - MID
TERM 5
Virulence Factors
DEFINITION 5
Virulence = degree of pathogenicityVirulence factors =
components of microbe which if lost reduce virulence (toxins
etc)Virulent strains of bacteria have virulence factors and
cause diseaseAvirulent strains of bacteria do not cause
disease as they lack virulence factors
