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21 Cards in this Set

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Typical Viral Replication Steps
Attachment, penetration, uncoating, early protein synthesis, NA replication, late protein synthesis, assembly and release
Early viral proteins
Generally involved in NA replication
Late viral proteins
Generally, structural proteins
Viral attachment
Via specific cell receptor
DNA Virus Replication
(generalities)
Replicated in host nucleus (except poxvirus)
Use host cell enzymes
Long replication times
RNA Virus Replication
(generalities)
Replicated in host cytoplasm
(except influenza)
Variable replication time (but may be short)
What NA strucutre do you need to translate protein?
(+) mRNA
Viral NA comes in multiple flavors. Therefore, imagine the multitude of ways you can create (+) mRNA
Viral Release Mechanisms
Enveloped viruses: budding (from plasma or nuclear membrane)
Naked viruses: cell lysis
Asymptomatic Viral Infection
No apparent cellular effect
Potential for transmission to others
Potential long-term complications (i.e. HPV and cervical cancer)
Viral Infection Cytopathology
May result from a number of different mechanisms (depending on viral life cycle)
May lead to the formation of inclusion bodies
Inclusion Bodies
Intracytoplasmic or intranuclear accumulations of virions, unassembled virion components or amorphous derbis (think: construction site). Visible under light microscopy and usual in diagnosis (b/c DNA virus, generally leave intranuclear inclusions bodies and RNA viruses leave intracytoplasmic inclusion bodies)
Hyperplasia (due to viral infection)
Expression of oncogenes, leads to unchecked cell replication. Reason why many viruses are implicated in multiple cancers
Viral Infection
(major characteristics)
Species, organ, cell specificity
Site of infection: greatest incidence respiratory and gastrointestinal tract (mucosa - not a fortified barrier) but decreased virulence. Skin/CNS infections are less frequent but more symptomatic
Viral Infection
(pathogenesis, general)
Acquisition, Incubation, Illness, Recovery, Resistance
Viral Infecotion
(pathogenesis, acquisition)
Airborn, contact, vehicle (i.e. food), vector, placenta
Viral Infection
(duration)
Persistant vs. non-persistant
Majority of human illness are transient (non-persistant) and relatively short term infections
If persistant, last a lifetime (i.e. HSV)
Surface vs. Systemic Non-Persistant Viral Infections
Surface: illness occurs at portal of entry (short incubation period)
Systemic: lymphohematogenous spread to distant organ (long incubation period)
Interferons
(general)
Early, non-specific response to viral infections
Alpha/Beta interferono have the greatest anti-viral effect
(Alpha, the "A" team - produced exclusively by profeossional APCs. Beta, the "B" team - more generalized production by prof/non-prof APCs, i.e. fibroblasts and epithelial cells)
Interferons
(mechanism of action)
Stimulate host anti-viral protein synthesis (will ultimately block viral protein synthesis)
Host Anti-Viral Proteins
Methylase
Nuclease
Protein Kinase
Phosphodiesterase
Immunopathology (due to viral infections)
Type III and IV hypersensitivity (immune complex deposition or attacking infected host cells or auto-immunity against self cells/proteins)