V2: Herpes Viruses Flashcards
How many families of Herpetoviridae are there?
How many are known to infect man with any regularity?
- 25
- 6
HHV1;
Common name?
Subfamily?
Common disease it causes?
- Herpes Simplex Type 1
- α
- Cold sores
HHV2;
Common name?
Subfamily?
Common disease it causes?
- Herpes Simplex Type 2
- α
- Genital Herpes
HHV3;
Common name?
Subfamily?
Common disease it causes? (2)
- Varicella-Zoster
- α
- Chickenpox
- Shingles
HH4;
Common name?
Subfamily?
Common disease it causes? (3)
- Epstein-Barr Virus
- Gamma
- Glandular fever
- Burkitt’s Lymphoma
What are the 4 main components of structure for the herpes virus?
- Envelope
- Tegument
- Capsid
- Genome
What is the tegument? (2)
- The space between the envelope and the capsid
- Contains virally encoded proteins and enzymes involved in the initiation of replication
What is the Capsid?
These viruses have a doughnut shaped capsomere of about 100-200 nm in diameter with an icosahedral nucleocapsid.
What is the life cycle of herpes virus (6)
- Virus Binds to the cell surface
- The envelope fuses with the cell membrane
- Capsid moves to nucleus
- mRna moves to cytoplasm
- Protein is synthesised
- Virus exostoses from plasma membrane
What does latency mean in regards to the herpes virus
Once a patient has become infected by herpes virus, the infection remains for life
How many proteins do HSV genomes encode?
At least 80 proteins
What enzymes are encoded by genome of HSV? (4)
What do they each do?
- DNA-dependent DNA polymerase
- Thymidine kinase (phosphorylates thymidine and other nucleosides)
- Ribonucleotide reductase (converts ribonucleotides to deoxyribonucleotide)
- Serine-protease (convert a scaffolding protein to its final form)
How many surface glycoproteins are encoded by HSV?
What are they involved in? (3)
- 11
- Attachment
- Fusion of the viral membrane with that of the host cell (gB)
- Immune escape and other functions
How is HSV-1 normally spread?
Mouth to mouth
How is HSV-2 normally spread?
Frequently spread sexually