Virology2
Terms
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- List the 6 stages of viral illness:
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1. Incubation
2. Prodrome
3. Onset
4. Acute
5. Recovery
6. Convalescance - When is viral material detectable by tests in these stages?
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Prodrome = occasionally
Onset = Frequently
Acute = Frequently - So the virus is directly detectable when the symptmos are:
- worst - onset and acute phase.
- When is specific antibody demonstrable in the illness?
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Acute phase - frequently
Recovery/convalescent - usually. - When is antibody NOT detectable?
- during Incubation and Prodrome.
- If a person tested positive for antibody during the incubation phase, what would this tell you?
- The person was previously vaccinated or naturally infected.
- List the 4 types of viral infections:
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1. Acute
2. Latent
3. Chronic
4. Prion - What is the fate of viruses in each infection type?
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Acute: eliminatd, doesnt persist
Latent: not eliminated; persists for months, years, or even life.
Chronic: Virus persists
Prion: Virsus persists. - What are the characteristics of an acute viral infection?
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1. Short incubation
2. Can recover virus but only during acute and onset. - What are the recovery qualities of Acute viral infections?
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1. Recovery COMMON
2. Confers resistance to future reinfections and w/ similar viruses. - What type of course does a latent virus generally follow?
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Primary infection = acute
During latency, illnes ranges from relapse to remission. - Compared to the acute virus only detectable in O and A phases, when is a Latent virus detectable?
- During Primary and Relapsing phases; not during remission.
- Immunologically, what causes a latent virus to exist?
- The host's immune system is ineffective in preventing relapse.
- Name 2 examples of an Acute virus:
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1. Variola
2. Poliomyelitis - Name 3 examples of a Latent virus:
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1. HSV
2. Varizella-Zoster
3. CMV - What is the general description of the disease course of chronic viruses?
- Incubation periods vary in length, so does the rest.
- When, during chronic infections, is virus recoverable?
- Regularly - it persists all through the infection.
- What differentiates a chronic from latent infection?
- The host's immunity is demonstrable in both, but does not even influence a chronic.
- Give 3 examples of a chronic virus:
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1. Rubella
2. CMV
3. Hep B/C - What are the characteristics of a prion infection?
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1. Incubation for months-years
2. Disease is relentless, progressive, and lethal. - When is prion detectable in such an infection?
- Both before onset and throughout the disease course.
- what were prions called previously?
- slow viruses
- what is the typical host immune response to a prion?
- Unpredictable! sometimes absent, weak, exaggerated, constant, or unconstant.
- Name 4 examples of Prions:
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1. Kuru
2. Progressive multifocal leukoencephalpathy
3. Subacute sclerosing panencephalitis
4. Creutzfeldt Mad cow disease - How is a prion different from a virus, structurally?
- Just protein; not genome.