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Host invasion by microorganisms (view source)
Revision as of 09:59, 22 August 2008
, 09:59, 22 August 2008→[[Viruses - WikiBlood|Viruses]]
=[[Viruses - WikiBlood|Viruses]]=
=[[Viruses - WikiBlood|Viruses]]=
[[Image:Virus structure.jpg|thumb|right|150px|Virus Structure - B. Catchpole, RVC 2008]]
[[Image:Virus structure.jpg|thumb|right|150px|Virus Structure - B. Catchpole, RVC 2008]]
[[Image:Viral replication.jpg|thumb|right|150px|Viral Replication - B. Catchpole, RVC 2008]]
[[Image:B Cell viral response.jpg|thumb|right|150px|B Cell Immunity to Viruses - B. Catchpole, RVC 2008]]
[[Image:T Cell viral response.jpg|thumb|right|150px|T Cell Immunity to Viruses - B. Catchpole, RVC 2008]]
==Structure==
==Structure==
Viruses are very simple structures that do not carry any cellular machinery of their own. They depend on host cells to replicate and flourish. As such, their structure is streamlined, containing only:
Viruses are very simple structures that do not carry any cellular machinery of their own. They depend on host cells to replicate and flourish. As such, their structure is streamlined, containing only:
All of these elements can be recognized by the host as foreign material, and will provoke an immune response. Viruses have an advantage if they are able to penetrate host cell walls in that they are then capable of masquerading as host cells. The immune system must then counter by killing off host cells it recognizes as infected.
All of these elements can be recognized by the host as foreign material, and will provoke an immune response. Viruses have an advantage if they are able to penetrate host cell walls in that they are then capable of masquerading as host cells. The immune system must then counter by killing off host cells it recognizes as infected.
==Pathogenesis==
==Replication==
==Replication==
Viral lifespans have three distinct phases:
Viral lifespans have three distinct phases:
*Infectious (extracellular): as they seek out a host target
*Infectious (extracellular): as they seek out a host target
*Replicative (intracellular): as they overtake the host cell's utilities to multiply
*Replicative (intracellular): as they overtake the host cell's utilities to multiply
*Dissemination (extracellular): as they leave the host cell and migrate to those surrounding
*Dissemination (extracellular): as they leave the host cell and migrate to those surrounding
==Prevention and control==
==Prevention and control==
*Viral evasion of immunity
*Viral evasion of immunity
**Latency: Viruses can "hide" in host cells until the immune system is suppressed
**Latency: Viruses can "hide" in host cells until the immune system is suppressed