General virology and lab diagnostic methods Flashcards
In what form do viruses contain nucleic acids?
In the form of linear or circular RNA in a single strand (most RNA viruses) and DNA in a double strand (most DNA viruses) in a (+) or (-) sense direction
What is the nucleic acid typically surrounded by? What is this made of?
Protein coat (caspid), made of subunits that form a helical, icosahedral or complex structure
What may nucleic acid complex with?
Nucleoprotein
Describe uneveloped viruses
- Typically resistant to acid and desiccation
- Typically cause infection via the oro-faecal route
What size are viruses?
Mostly 20-300nm
Are viruses visible by light microscope?
No
What is the viral envelope derived from?
It is a lipid bilayer derived from the host cell
What determines the Baltimore classification of the virus?
Nucleic acid type (and replication strategy)
What are methods of detecting virus or virus fragments in the blood or CSF?
ELISA
PCR (or RT-PCR)
Plaque (or other infectious centre) assays
Hemagglutination
What are methods for detecting specific antibody?
ELISA, hemagglutination inhibition
Baltimore class I
Double-stranded DNA viruses
Baltimore class II
Single-stranded DNA viruses
Baltimore class III
Double-stranded RNA viruses
Baltimore class IV
Single-stranded RNA viruses - postive-sense
Baltimore class V
Single-stranded RNA viruses - negative-sense
Baltimore class VI
Positive-sense single-stranded RNA viruses that replicate through a DNA intermediate
Baltimore class VII
Double-stranded DNA viruses that replicate through a single-stranded RNA intermediate
Draw the structure of a virus
See folder with notes
describe B1
Nuclear replication
Requires host polymerase
Dependent on cell cycle
Cancer
Describe b2
Nuclear replication
Describe B3
Cytoplasmic replication
Little dependence on polymerase
Segmental genome
Monocistronic
Describe b4 and b5
cytoplasmic replication
+ can directly access ribosomes
- RNA must be transcribed to mRNA
Describe b6
reverse transcribed DNA intermediate with integration
Describe b7
gapped DNA requiring RT step
Example of B1
Herpes
Example of 4
Polio
HCV
Examaple of V
Influenza
Example of VI
HIV
Example of VII
HBV
Examples of enveloped viruses
HIV
Influenza
HepC
Herpes
Examples of non-enveloped viruses
Adeno and papilloma
What is eclipse phase?
Period immediately after infection before new virus production
What is burst size?
Number of new infectious particles produced by an infected cell
