Herpes Virus Flashcards
can herpesviruses be distinguished from each other via electron microscopy?
NO!
they have identical morphology
properties of herpesviruses
enveloped double stranded DNA viruses - 150kb
latent/persisten infections
3 subfamilies of herpesviruses
alphaherpesviruses (HSV1 and 2)
betaherpesviruses (CMV)
gammaherpesviruses (HHV-8)
reactivation of herpesviruses is more likely to take place during
periods of immunosuppression
the genome of HSV-1 and HSV-2 share
50% to 70% homology
the natural host for HSV
humans
why is there a challenge for a vaccine for herpesviruses?
there is lots of variation
four layers of herpesviruses
ds DNA genome
icosapentahedral capsid
tegument
envelope
what is tegument?
amorphous protein coat
additional protection
the herpesvirus genome is replicated
by the virus encoded DNA polymerase
infections of human herpesvirus are
LIFELONG :(
herpesvirus establishes latency in
the craniospinal ganglia
alphaherpesvirinae
Human herpesvirus 1 - simplex 1
Human herpesvirus 2 - simplex 2
Human herpesvirus 3 - Varicella zoster
Gammaherpesvirinae
Human herpesvirus 4 - Epsteinbarr birus
Human herpesvirus 8 - Kapok’s sarcoma
Betaherpevirinae
Human herpesvirus 5 - CMV
Human herpesvirus 6 - sixth disease
Human herpesvirus 7
how is HSV spread?
by contact
shed in saliva, tears, genital and other secretions
most common cause for infection of HSV
kiss given to child from a person shedding the virus
what percent of the population acquires HSV infection through the genital route?
10%
HSV-1 establishes latency in
the trigeminal nerve ganglion
HSV is involved in a variety of clinical manifestations which includes
acute gingivostomatitis
herpes labialis - cold sores
ocular herpes
herpes genitalis
cutaneous herpes
meningitis
encephalitis
neonatal herpes
herpesviruses simplex 1 and 2 target
sensory neurons
what is the prevalence of HSV-2?
it is 2nd in terms of prevalence relative to HPV
Pregnant women with genital herpes should
talk to their doctor
it can be passed to the child during childbirth
attacks of HSV 1 and 2 can be brought on by
illness
fatigue
stress
immunosuppression
trauma to the affected area
menstruation
is there a cure or vaccines for HSV-1 and 2?
NO!
treatments for HSV-1 and 2
topical anesthetics (lidocaine) - itching and pain
prescription strength medications (acyclovir) - reduce healing time and pain
otc treatments
otc treatments for HSV 1 and 2
abreva (docosanol 10%)
shortens duration, does not cure
acyclovir comes in
patches, tablets, and cream
mechanism of action of acyclovir
chain terminator that competes with natural GTP for incorporation into viral DNA
how can acyclovir incorporate into viral DNA?
it is converted from acyclovir monophosphate to triphosphate
nucleotides are also triphosphates
common side effects of acyclovir and valacyclovir
photosensitivity
nausea
vomiting
Varicella-Zoster (HHV-3)
chicken pox
incubation: 14-16 days
highly contagious
symptoms: itchy, malaise, fever
chickenpox vaccine led to
a 90% reduction in deaths
treatment for HHV-3
calamine lotion
NON-aspirin fever reducers
acyclovir
HHV-3 remains
dormant in dorsal root ganglia for years
when does HHV-3 reactivate?
later in life, usually in persons older than 50 years
one out of _____ people 60 years or older will get shingles
three
is there treatment of cure for the severe pain caused by shingles?
NO!
shingles may also lead to serious complications such as
pneumonia
hearing problems
complication involving the eye
postherpetic neuralgia
severe pain in the area where shingles rash occurred
can last weeks to months
10-13% of patients
Shingrix
more than 90% effective at preventing shingles and long term nerve pain
shingle specific counseling points
avoid contact with people who have not had chickenpox or vaccine
wear loose fitting clothing
cover lesions
avoid the use of topical creams and adhesive dressings
keep the rash clean and dry
avoid sharing clothing/towels
avoid direct sunlight
HHV-5 and 6 are spread by
saliva and secretions
HHV-5 (cytomegalovirus)
infects epithelial cells, macrophages and T cells
causes cells to fuse to form giant cells
symptoms mimic mononucleosis
______% of adults over 40 have had a CMV infection
80%
CMV infection in an HIV+ individual is
a MEDICAL EMERGENCY
when CMV infection becomes active during pregnancy, the virus can
cross the placenta
10% of infected babies have symptoms at birth such as
prematurity
jaundice
purplish rash
seizures
pneumonia
diagnosis of CMV
PCR test for viral DNA in blood
treatment of CMV
ganciclovir (nucleoside)
HHV-6 (sixth disease)
commonly seen during childhood (6 months - 2 years old)
fever
contagious (when fever is present)
treatment for HHV-6
Non aspirin fever reducer such as an NSAID
why do we not use aspirin with a viral illness?
Reye syndrome
HHV-4 (espstein barr virus)
infects B cells (lymphocytes)
HHV-4 can cause
Hodgkins disease
lymphoma
multiple sclerosis
infectious mononucleosis
immune deficiency
symptoms of Epstein Barr virus
fatigue
fever
swollen lymph nodes
swollen liver
rash
treatment for Epstein Barr virus
rest
hydration
OTC remedies for pain and fever (non aspirin)
HHV-8 (Kaposi’s Sarcoma)
causes one of the most common cancers affecting persons with HIV/AIDS
sole treatment of HHV-8
HAART in non-visceral KS
eye infections caused by
herpes simplex virus
gingivostomatitis caused by
herpes simplex type 1
pharyngitis caused by
epstein barr virus
cytomegalovirus
skin infections caused by
varicella zoster virus
human herpesvirus 6
sexually transmitted diseases
herpes simplex type 2
