HSV, VZV Ryan

Question 1

describe herpesvirus structure

Answer 1

icosahedral capsid, lipid env (from host cell), dozen glycoproteins (from virus–help attach, release)

Question 2

describe herpesvirus genome

Answer 2

linear ds DNA

Question 3

where does herpesvirus replication, assembly occur

Answer 3

nucleus

Question 4

lifethreatening herpesvirus infections occur when

Answer 4

immunocomp and neonates

Question 5

3 classifications of herpesvirus

Answer 5

alpha, beta, gamma

Question 6

what are the alpha herpesvirus

Answer 6

HSV-1, HSV-2, VZV

Question 7

what do all 3 alpha herpesviruses have in common?

Answer 7

replicate in epith cells, neutropic latency, BLISTERS

Question 8

3 important proteins in alpha herpes lytic cycle?

Answer 8

IE (TF), E (repln), L (structure)

Question 9

LYTIC CYCLE

Answer 9

1. bind hep sulfate on host cell surface, e-static
2. lock and key intrxn with glycoprots (fusion)
3. transloc –> nuc
4. IE expressed from virus; host RNA pol
5. E protein req for rep’n
6. virus DNA pol rep’n in nucleus –> L genes exp
7. L genes –> cyto, translated, –> nuc
8. packaged in nuc, exocytosed
9. virus rel from ER –> trans golgi network, take env
10. bud

Question 10

what cells do alpha herpesvirus replicate in

Answer 10

epith but ALSO neurons!

Question 11

describe herpesvirus neuronal rep’n

Answer 11

uptake by periph sensory neurons from progeny of epith replication. occurs soon after infection

Question 12

as herpesvirus replicates in neurons, what happens to progeny?

Answer 12

trans-synaptically transported retrograde towards CNS

Question 13

challenges to herpesvirus for latency?

Answer 13

prevent lytic rep’n, apop of neuron, and immune recognition

Question 14

how does herpesvirus stay latent?

Answer 14

Latency-assoc transcript: LAT

Question 15

role of LAT

Answer 15

prodcues miRNAs that repress viral gene expression, apop, and CD8

Question 16

what herpesviruses express LAT

Answer 16

HSV. not VZV

Question 17

where does HSV-1 cause infection

Answer 17

skin, ocular, encephalitis

Question 18

where does HSV-2 cause infeciton

Answer 18

Urogenital, meningitis

Question 19

when is herpesvirus fatal

Answer 19

CNS, dissemination esp neonate and immunocomp

Question 20

HSV pathogenesis

Answer 20

• secretions –> breaks in skin/mucosa
• primary inf often not noticed
• replicate in epith cell at site of inf –> nodes
• also taken up by sensory periph nn –> latency

Question 21

recurrence of HSV?

Answer 21

not as painful if the primary infection was noticeable/ painful. Can occur 5-8x/year. due to lapse in immunity. Remain local bc so many Abs

Question 22

HSV epidemiology

Answer 22

adult US HSV-1: >55%
adult US female HSV-2: 20%
adult male/young adult HSV-2: 10%

Question 23

dx HSV

Answer 23

clinical dx. Serology only for primary inf
culture was gold standard, but now PCR if needed like in meningitis
Tzanck smear: take base of vesicle, look for giant cell

Question 24

VZV pathogenesis

Answer 24

primary –> chickenpox. VERY communicable aero
winter
fever, itchy rash on scalp/trunk.
in adult? severe, PNA

Question 25

replication of VZV

Answer 25

rep in nodes, primary viremia, rep in organs, secondary viremia, then RASH

Question 26

zoster

Answer 26

VZV reactivated infection. SHINGLES! sudden onset pain, rash on unilat thoracic dermatome or forehead rash 2-4 weeks, pain LONG (posttherpetic neuralgia)

Question 27

dx VZV

Answer 27

clinical dx. Tzanck smear poss