#13 Neurotropic Herpes Flashcards
General on herpseviruse
size:
genome:
enveloped?
Large dsDNA icosahedral
enveloped and tegumented
Types of herpes simplex virus
HHV-1 (more common)
and HHV-2 (alpha)
Longevetiy of herpse
lasts 2 hours on skin
4 on plastics
doesn’t do well outside host
Varicella Zoster Virus (VZV)
Short replication cycle, latency mostly in sensory ganglia, broader host ranges
HHV-3
HHV-3
Varicella zoster virus (herpesvirus)
shorter replication
latent in sensory gang
broad host
What enZ do herpesviruses encode
Defining biological properties:
encode collection of enZ involved in nuceotide metabolism (thymidine kinase), DNA synthesis (DNA polymerase) and protein kinase
Synthesis of viral DNA and capsid assembly occur in the ______ while the rest of the virion is put together in _______
nucleus
cytoplams
Herpese virus has:
lytic and latent stages
Herpes virus starts with:
Binding and fusion→ transport DNA into______
→ viral_______ degrades host mRNA
→ viral transcription factor _______and localizes to nucleus to initiate viral gene transcription
→ Viral DNA circulizes
nucleus
vhs
VP16
→ HSV αgene transcribed by __________
ome αgene products activate __________→
some Beta genes needed for __________→
Viral DNA syntesis triggers expression of _____
host RNA polymearse II
β genes
viral DNA synthesis
γ genes
gamma products are stuctual components of______→ viral DNA packed into________
→ filled viral capsid bud through host mmbs to make mature vrion that exits the cell
virion
capsid
Latent: Circular viral DNA associated with host nucleosomes (viral chromatin) and maintaned as______→
episome
Latantly: very little viral gene expression (most lytic genes are trnascriptionally suppressed via viral ________→ poorly defined mechanisms trigger reactivation
chormatin- assocated histones
REactivation of herpes?
physiological triggers of reactivation:alterations in immune system (stress or drug therapies)
US population; majority are seropositive for _____and 17% seropositive for _____
1 in 4 females) and (1 in 8 males)
HSV-1
HSV-2
resevroius of herpes
humans only
Transmission of herpes
is by fomites common?
Transmission:
a. person-person and RARELy by fomites
b. intrauterine is rare
c. Perinatual during birth
d. Sexually: skin/skin, Gen-Gen, Oral-Gen, oral-oral
HSV-1 more commonly shed from
HSV-2 more commonly from
oral cavity
genital tract
- Virus transmitted to mucosa or abraded epithelium→ get robust LYTIC replication=
Primary infection
- HSV may_____ systemically and seed to several organs (adrenals, liver, CNS)
disseminate
Virsus infects sensory neurons innervating site of inoculation—______transport to sensory ganglia = LATENTCY
retrograde
site for latent HSV-1 =
latent HSV-2=
trigeminal
sacral
Latency: characterized by expression of viral mRNA called __________
LATs (Latency Asociated Transcripts)
LATs are_______ translated into protein and fnx to prepress HSV gene expression
NERVER
Some latent capsids subject to ________ transport with mature virions that get back to site of inocculation
ANTEROGRADE
frequency of reactivation is _____ in untreated HSV2+ people with subclincial reactivation around ______ on any given day
HIGH
25%
possible of sero+ perons with diff strain of HSV but uncomon
Exogenous Reinfection