42 terms

Herpesviruses I(HSV1, HSV 2, VZV)

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Terms in this set (...)

hallmark of herpesvirus?
all establish latent infections
which strands of herpes are the least common
2 and 8
Seroprevalence
overall occurrence of an infection in a population based on antibody testing
features of herpesvirus
large; enveloped; icosahedral capsids;

contains large dsDNA
two enzymes that promote viral replication
thymidine kinase and DNA polymerase; primary target for anti viral
genome of herpesvirus
very large number of genes; remarkable arrangement of reiterated sequences;
alpha vs beta vs gamma herpesvirinae
alpha - fast growing, cytolytic, infects mucoepithelial cells; latent in neurons (1,2,VZV)


beta - slow growing, cytomegalic, infects and latent in epithelial cells, endothelial cells and leukocytes

gamma - variable growth cycles; lymphoproliferative; infects and latent in lymphocytes and other cells (EBV)
productive vs latent infection
productive - host cell supports virus growth; progeny visions produced and released


latent - virus is "hidden" / "inactive"; no virus particles produced; reservoir for reactivation and recurrent infection;

reactive triggered by fever, stress, menses, UV light, trauma, immune suppression
during latency, what genes are expressed?
few genes are expressed - only for eminence; they don't want to be recognized, they want to hang out in the cell;
lytic vs latent infected cell types
lytic - many cell types will be infected versus latent where a few (one or two) will be infected;
spread of herpes viruses
person to person; no intermediate host or animal reservoir

all ages; no seasonality;
what does disease severity depend on?
disease severity is high w/ primary infection in immune impairment

severity is low w/ recurrent infection in the immune competent
what type of immune response is important ?

immune evasion
CELL MEDIATED!

T cells are critical;

antibodies SOMEWHAT effective; complement is not;

BUT immune evasion - encode proteins that interfere w/ MHC class I antigen presentation
Herpes Simplex Virus
two serotypes - HSV-1 and HSV-2

HSV-1 - respiratory spread in childhood; infects oral mucosal epithelium; latent focus in trigeminal ganglia; recurrences less

HSV-2 - spread by intimate sexual contact infects genital mucosa; latent in lumbrosacral dorsal root ganglia; recurrences common


but 20-50% of genital infections are HSV1

5-20 of oral are 2
HSV skin infections
vesicles -- pustules -- Ulcers -- crusts

VPUC
Gingiovostomatitis

seen in who?
symp?


what happens recurrent?
most common primary symptomatic HSV-1 infection

generally seen in children and young adults

fever, malaise, irritability, headache, vomiting, lymphadenopathy, 1-2 days prior to lesions

strikingly swollen and tender gums

recurrent -- recurrent cold sores;
Genital herpes infections
women more susceptible then men;

most cases acquired from asymptomatic partner;

HSV-2 genital ulcers increase risk of acquiring and transmitting HIV-1
neonatal herpes -

primarily caused by what?

three syndromes
transmitted through infected birth canal; most women are symptomatic;

primarily caused by HSV-2

syndromes

1. localized skin eye mouth (SEM) infections

2. encephalitis

3. disseminated disease
Ocular you can get....
herpes keratoconjuntivitis -- inflamed cornea and inflamed conjunctiva

HSV1 infection of eye;

result of primary infection w/ continuous recurrence over time

1 cause of infectious blinds in developed world;

may have dendritic ulcers
herpes encephalitis


what will you see involved?
most common cause of acute sporadic encephalitis

primarily HSV1

mortality high if untreated; morbidity significant delay in treating

you will see TEMPORAL LOBE INVOLVEMENT (necrotic)

(man putting cereal on his head, plants on his arms)


other finds - RBC in CSF, CSF pleocytosis, behavioral changes, dec level of consciousness
neonatal encephalitis vs community
neonatal is more type 2; community is type 1
encephalitis; temporal lobe; community acquired; sporadic
type 1
HSV meningitis
recurrent episodes of HSV meningitis; usually caused by HSV2 from genital infections

aseptic; can have these annually - it is benign, you don't treat, no neurologic sequele over time
infections in compromised hosts
locally invasive skin infections; any individual with deficiency cellular immunity

eczema herpeticum - caused by 1 or 2; common in patients with atopic dermatitis;

progress slowly cause necrosis;
other skin infections - what may you see? a baby sucking thumb, a mother that is infected and bites her babies nails
HERPETIC WHITLOW

can be 1 or 2

traumatic herpes

local lesions on fingers and hands

enters through abrasions and openings in skin
wrestlers may get what kind of herpes
herpes gladiatorum (mat herpes)
Varicella zoster virus

primary vs recurence
primary - varicella (chickenpox)

recurrence (herpes zoster) shingles
varicella epidemiology

at an older age?
highly contagious

at older age -- pneumonia !! majority of morbidity and mortality in teens and adults
what does varicella look like
starts out maculopapular and then small, fluid filled vesicles with central dimple on a red base; rash is itchy

all stages of rash at any given moment
varicella vs small pox
small pox -- all same stage

varicella you will see multiple stages all at the same time
contagious for chicken pox?
1-2 d before rash and 4-5d after rash onset
other symptoms of chicken pox
prodrome, fever, malaise, pharyngitis;
where does rash begin
rash begins on chest, back, and face; spreads rapidly
varicella complications
can spread to cerebellum and cause ataxia; pneumonia in older; hepatitis;

immunocom - life threatening pneumonia, encephalitis and progressive disseminated varicella
disseminated varicella-zoster
Kaposi's varicelliform

AIDS
Zoster epidemiology
age is most important risk factor;

incidence progressively inc w/ age - inc dramatically after 50

zoster recurrences only common in immunocompromised
zoster features
unilateral vesicular rash that follows a deermatomal distribution;

does not cross midline

when tip of nose is involved, eye is often infected;
ramsay hunt syndrome
herpes zoster oticus

affects facial nerve near infected ear

herpes zoster oticus is a viral infection of the inner middle and external ear

facial paralysis and hearing loss on same side as affected ear;
zoster complications
post herpetic neuralgia

persistence of pain for 3 months or so after healing of rash;
granulomatous angiitis
vasculitis of small blood vessels in CNS
varicella vs zoster vaccine
zoster is just larger about
antiviral drugs for HSV/VZV
acyclovir, valacyclovir, famciclovir, idoxuridine, trifluridine, foscarnet