Virulence Factors Flashcards
1
Q
Virulence Factors
A
factors that enhance disease development in a host by allowing the pathogen access to the host as well as evading host defence mechanisms.
2
Q
Virulence
A
the degree to which a pathogen affects or harms the host.
3
Q
Pathogenesis
A
the mechanism that leads to a disease
4
Q
Adherence Factors
A
- Ability to adhere to host cells.
- Bacteria produce fimbriae or pili to resist physical removal.
5
Q
Invasion Factors
A
- Ability to enter host’s tissues, multiply and spread.
- Many bacteria have a capsule (composed of polysaccharides) which evade a host’s ability to recognise it and destroy it.
- Some bacteria secrete enzymes to break down tissues.
6
Q
Capsule
A
- Resist host immune defence by preventing phagocytes adhering to them.
- Composition of capsule prevents adherence of immune cells.
- Capsule makes cell larger, making it more difficult for immune cells to engulf the pathogen.
7
Q
Toxins
A
- Damage host tissues – example = can cause fever, inflammation etc.
- Endotoxins (produced inside bacteria) or exotoxins (part of outer part of cell wall. Released upon bacterial death.
8
Q
Lifestyle changes
A
- Change pathogenicity in response to the environment.
- Example = fungal spores: inactive
