12.HHV3_VZV_Flashcards

Question 1

What is HHV-3 (Varicella-Zoster Virus)?

Answer 1

HHV-3 is the virus responsible for Varicella (Chickenpox) and Herpes Zoster (Shingles). It is a small virus with no RNA polymerase and only 1 serotype with no genetic variation.

Question 2

What are the symptoms of Varicella (Chickenpox)?

Answer 2

1. Crops of papulovesicular rash starting on the trunk, with centripetal distribution.
2. Itchy (pruritic) rash progressing to vesicles, ulcers, and crusts.
3. Highly contagious with generalized vesicular rash.

Question 3

What is the incubation period for Chickenpox?

Answer 3

The incubation period for Varicella (Chickenpox) is ~14 days (skin-to-rash).

Question 4

What are the modes of transmission for Chickenpox?

Answer 4

1. Direct contact.
2. Respiratory droplets.
3. Congenital transmission (TORCH): Can cause Congenital Varicella Syndrome if infection occurs in the first 20 weeks of pregnancy.

Question 5

Where does VZV become latent in Chickenpox?

Answer 5

VZV becomes latent in sensory ganglia, specifically the dorsal root ganglia.

Question 6

What age group is typically affected by Chickenpox?

Answer 6

Chickenpox typically affects children.

Question 7

What are the complications of Chickenpox?

Answer 7

1. Rare in normal children.
2. Severe complications include:
   
   • Pneumonia in pregnant women.
   • Congenital Varicella Syndrome: Limb hypoplasia, cutaneous scars, microcephaly, chorioretinitis.

Question 8

What are the symptoms of Herpes Zoster (Shingles)?

Answer 8

1. Painful vesicles along sensory nerves of the head and trunk.
2. Rash is always unilateral.
3. Common sites: Trigeminal nerve (ophthalmic branch involvement can lead to Zoster keratitis).

Question 9

What is the incubation period for Herpes Zoster (Shingles)?

Answer 9

The incubation period for Shingles is 10-15 days after reactivation.

Question 10

What triggers Herpes Zoster (Shingles)?

Answer 10

Reactivation of latent VZV, typically in adults and immunocompromised patients (ICP).

Question 11

What are the complications of Herpes Zoster (Shingles)?

Answer 11

1. Post-herpetic neuralgia: Persistent nerve pain, common in the elderly.
2. Pneumonia in immunocompromised patients (can be life-threatening).

Question 12

What are the differences between Chickenpox and Shingles in terms of disease, transmission, latency, age group, and complications?

Answer 12

1. Disease:
   
   • Chickenpox: Centripetal rash (mild in children).
   • Shingles: Painful vesicles along sensory nerves (unilateral).
2. Transmission:
   
   • Chickenpox: Direct contact, respiratory droplets, congenital.
   • Shingles: Reactivation of latent VZV.
3. Latency:
   
   • Chickenpox: Latent in dorsal root ganglia.
   • Shingles: Reactivation in adults.
4. Age Group:
   
   • Chickenpox: Children.
   • Shingles: Elderly or immunocompromised adults.
5. Complications:
   
   • Chickenpox: Congenital Varicella Syndrome, pneumonia.
   • Shingles: Post-herpetic neuralgia, pneumonia.