Microbial Pathogenesis Flashcards
Define: Parasite
An organism that lives on or in a secondary organism called a host
Define: Pathogen
& Name 3 kinds
An organism that causes damage to the host.
Opportunistic, Primary and Zoonotic
Define: Pathogenicity
The ability of a microorganism to cause disease
Define: Virulence
The degree of pathogenicity
Define: Infection
Refers to the growth of the microorganism in a host, it is not synonymous with disease
Micro-organisms have a variety of traits that interact with a host. What do they enable the pathogen to do?
- Enter a host
- Adhere to cells
- Gain nutrients
- Evade the immune system
Micro-organisms use certain factors called…
Virulence factors
What are Adhesins?
Virulence factors that allow micro-organisms to adhere to host cells
What are Invasins?
Virulence factors that allow micro-organisms to breach anatomical barriers of the host
What are Aggressins?
Virulence factors that aid the colonisation of host tissue by releasing toxins and tissue damaging enzymes
What are Impedins?
Virulence factors that allow micro-organisms to have strategies to overcome non-specific defence, especially anti-phagocytic mechanisms.
As well as strategies to overcome specific immunity, the most important of which is production of IgA proteases (impedins), molecular mimicry and immunogen variability
Name some features of Host-pathogen interactions (?)
- Depends on the rate of adaptive response
- Adaptation leads to stability
- Uncommon for a microbe to cause exactly the same disease in all infected individuals
- Depends on the virulence of the pathogen
Define: Attenuation
When a pathogen’s virulence is reduced (i.e in cultured conditions)
