Herpes Simplex I and II

Question 1

Define the structure of Herpes Virus

Answer 1

Large, enveloped double stranded DNA

Question 2

SIMPLEX 1 above the waist

Answer 2

HSV 1

Question 3

SIMPLEX 2 below the waist

Answer 3

HSV 2

Question 4

REPLICATION

Answer 4

Lytic: spreads in epithelial cells
Late: stays in neuroglial cells

The capsid of this virus is shuttled to the nucleus (genome of DNA is circularized)

Transcription: mechanism in a cascade fashion

**Expresses three distinct class of mRNA **

Question 5

The importace of heparan in this virus

Answer 5

The glycoproteins on the virus’s envelope interact with cellular receptors: Heparan sulfate so it can result in fusing onto the cell membrane!!!

Question 6

Epidemiology:

1. Reservoirs of the herpes simplex virus
2. Seroprevalence in humans increase with ?
3. Developing countries incidents:
4. Carriers ?

Answer 6

1. NO ANIMAL RESERVOIRS
2. Seroprevalance increases with AGE
3. 90 % of the population of developing countries have HSV-1 antibody before age 30
4. Usually asymptomatic people

Question 7

Describe the Acute Stage of Infection (HSV)
Lytic stage of the infection:

Answer 7

infects mucoepithelial cells
Ballooning degeneration of epithelial cells
produces multinucleated giant cells
Eosinophilic inclusions
Neutrophil infiltrates
Monocyte infiltrate

Question 8

Define in terms “ Latent Infection” of HSV

Answer 8

Affects sensory ganglion cells

HSV genes are inside each latently infected neuronal cells but do not cause cell death

ONLY a small portion is transcribed – because latent infection DOES not require synthesis of EARLY and LATE polypeptides

Antiviral drugs do not eradicate virus in its latent stage

Reactivation: exposure to sun, fever or trauma

Question 9

In which nerves is HSV 1 found or located ?

Answer 9

Trigeminal nerves
Superior cervical nerves
Vagal nerve ganglia

Question 10

In which nerves is HSV 2 located?

Answer 10

Below the waist
S2 - S3

Question 11

Reactivation of HSV occurs due to

Answer 11

1. Trauma
2. Fever
3. Exposure to sun