III - A. Virology | 10. Herpesviruses (HHV1, HHV2, VZV)

Question 1

I. Alpha-herpesviruses in general
1. What are the genetic material and morphology?

Answer 1

• dsDNA genome
• Isocahedral capsid
• enveloped viruses
  => they are (generally) acyclovir sensitive

Question 2

I. Alpha-herpesviruses in general
2. List 3 human pathogen alphaherpesviruses?

Answer 2

Question 3

I. Alpha-herpesviruses in general
3. what is the replication strategy of Alpha-herpesviruses?

Answer 3

unique replication strategy
* DNA of the virus enters the host’s nucleus
* latency for life ➡ reactivation can occure any time
* or immediate active proliferation and symptoms due to cell lysis

Question 4

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
1. What are the features of Herpes simplex 1 and 2?

Answer 4

1. Quite similar viruses
   - can differentiate them based on glycoprotein
2. Cause epithelial and nervous tissue infection
3. Lytic cycle is 2-3 days long
   - massive cell death when virions are released
   - vesicles (errupts, ulcerates, scars)

Question 5

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
2. What is the source of infection of Herpes simplex 1 and 2?

Answer 5

infected individual (symptomatic or asymptomatic as well!)

Question 6

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
3. What is the route of transmission of Herpes simplex 1 and 2?

Answer 6

through skin or mucosal microfractures

Question 7

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
4. What is the pathomechanism of Herpes simplex 1 and 2?

Answer 7

• Primer epithelium infection at the infection site => lytic cycle
• migrates to sensory ganglia through peripherial nerves
• latency in peripherial sensory neurons, reactivation during immunosuppression and migration into regional skin where symptoms re-emerge

Question 8

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
5. What are the diseases caused by HSV1 & HSV2?

Answer 8

Question 9

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
6. What is the diagnoses for HSV1 & HSV2?

Answer 9

• based on signs and symptoms
• sampling of vesicles for PCR
• sampling from the base of the ulcers for smear preparation
  (Tzanck smear)
• liquor sample if encephalitis is present
• serology is not useful as majority of the population is seropositive

Question 10

II. Herpes simplex 1 and 2 (HSV1 & HSV2 OR HHV1 & HHV2)
7. What is the therapy for HSV1 & HSV2?

Answer 10

• acyclovir, famcyclovir (local therapy)
• valacyclovir, pencyclovir (oral)
• if resistance is present: cidofovir, vidarabin

Question 11

III. Varicella-zoster virus (VZV)
1. What are the features of varicella-zoster virus (VZV)?

Answer 11

• cause of chickenpox and shingles
• causes epithelial and nervous tissue infection
• lytic and latent-reactivating infections

Question 12

III. Varicella-zoster virus (VZV)
2. What is the source of infection of varicella-zoster virus (VZV)?

Answer 12

infected and symptomatic individual

Question 13

III. Varicella-zoster virus (VZV)
3. What is the route of transmission of varicella-zoster virus (VZV)?

Answer 13

• respiratory droplets
• or through microfractures of the skin or mucous membranes

Question 14

III. Varicella-zoster virus (VZV)
4. What is the pathomechanism of varicella-zoster virus (VZV)?

Answer 14

1. Local proliferation in infected conjunctiva or upper respiratory tract
2. spreads to regional lymph nodes and blood stream
3. infects the liver and the spleen, then through a secondary viraemia it infects the vascular endothel and the epithel cells of the skin
4. After the acute infection, viral latency occurs in the spinal ganglia
   - 1 out of 5 individual will be affected by reactivation
   later in their life (usually when they are older than 50) => reactivation is called shingles

Question 15

III. Varicella-zoster virus (VZV)
5A. What are the diseases caused by VZV?

Answer 15

• Chicken Pox
• herpes zoster (shingles)
• Herpes zoster Ophthalmicus
• Congenital Varicella Syndrome (when pregnant women are affected and how it affects off
  spring)

Question 16

III. Varicella-zoster virus (VZV)
5B. What are the signs and symptoms of Chicken Pox?

Answer 16

• Fever, pharyngitis, rhinitis
• Asynchronous rash
• Adults present with pneumonia and encephalitis
• In immunocompromised

Question 17

III. Varicella-zoster virus (VZV)
5C. What are the signs and symptoms of herpes zoster (shingles)

Answer 17

• Localised to one or few dermatomes unilaterally => rash, pain!
• Dissemination may occur in immunosuppressed patients

Question 18

III. Varicella-zoster virus (VZV)
5D. What are the symptoms of Herpes zoster Ophthalmicus?

Answer 18

• Vision loss when CN1 is involved

Question 19

III. Varicella-zoster virus (VZV)
5E. What are the symptoms of Congenital Varicella Syndrome?

Answer 19

Congenital Varicella Syndrome (when pregnant women are affected and how it affects off
spring)
- Limb hypoplasia
- Cutaneous dermatome scarring
- Blindness

Question 20

III. Varicella-zoster virus (VZV)
6. What is the diagnosis for VZV?

Answer 20

• mainly based on the clinical signs and symptoms
• Tzank smear (shows Cowdry type A, intranuclear inclusions)
• PCR or antigen detection is possible from samples taken from the lesions

Question 21

III. Varicella-zoster virus (VZV)
7. What is the therapy for VZV?

Answer 21

Question 22

III. Varicella-zoster virus (VZV)
8. What is the prevention for VZV?

Answer 22

• Live, attenuated vaccine for children and seniors
• Booster for elders to prevent shingles