24 - DNA Viruses Part 1 (Stapleton) Flashcards
naked DNA viruses
papilloma
parvoviridae
adenoviridae
enveloped DNA viruses
herpesvirus
hepadnavirus
poxviridae
herpesvirus characteristics
large dsDNA icosahedral enveloped establish lifelong latency in host severe disease in immunocompromised 8 types
entry of herpesvirus
receptor mediated fusion of envelope with plasma membrane
transcription of herpes virus
Intermediate early-start transcription
early genes-replication
late genes-structural genes
lytic life cycle DNA synthesis
nucleoside kinase phosphorylates nucleoside needed for DNA transcription
DNA polymerase transcribes new viral DNA
herpes replicates episomally
independent of host chromosome
herpes egress
assembly in nucleus
traverse nuclear membrane
enter golgi body and traffic to plasma membrane to leave cell
herpes latency
viral lytic gene is turned off
latent gene is turned on-highly restricted, only a few genes
latent and lytic viruses are different population of cells
herpes pathogenesis
transmission contact with secretions
lytic replication in cells
virus passed to population for latency and maintained in these cells for remainder of hosts life
HSV-1
common worldwide
spread by close contact
asymptomatic and symptomatic sheddin
HSV-1 infection
initially at epithelial cells at mucocutaneous surfaces
spread to sensory nerves
ascend axons to nearest ganglion
cold sore latency where
trigeminal gangion
HSV-1 reinfection
traffic down sensory neuron to infect epithelial cells at original infection
lytic infection
epidermal destruction
HSV-1 symptoms of primary infection
asymptomatic primary gingivostomatits ocular herpes herpetic whitlow genital herpes
HSV-1 pathology
diagnostic
multinucleated giant cells
inclusion bodies
HSV-1 symptoms of reinfection
asymptomatic cold sore herpes keratitis herpetic whitlow herpes encephalitis genital lesion
HSV-1 in immune deficiency
severe and long lived disease
visceral disease
encephalitis
HSV-2 characteristics
worldwide
less prevalent than HSV-1
spread sexually
HSV-2 latency
in spinal gangion
HSV-2 primary infection
asymptomatic
genital herpes
neonatal herpes
primary gingivostomatits
HSV-2 reinfection
asymptomatic
genital herpes
cold sores
varicella zoster virus characteristics
worldwide
respiratory spread
no asymptomatic sheddin
chicken pox symptoms
fever
malaise
pruritic vesicular rash
chicken pox pathogenesis
respiratory infection
traffic from lungs to organs to skin
virus released by sneezing or coughing
chicken pox latency
ascend up sensory axons to sensory ganglia
reactivation of chicken pox
herpes zoster/shingles
rash on single dermatome
post herpetic neuralgia
chickenpox vaccine
live attenuated virus
2 doses
shingles vaccine
adults >60 years
EBV characteristics
worldwide
spread by close contact (kissing disease)
EBV pathogenesis
replication in oropharyngeal cells
spread to circulating B cells-swollen lymph nodes and spleen
viremia from replication in circulating B cells
EBV reactivation
viral spread to epithelial cells in oropharynx
oropharyngeal and B cells shed EBV in saliva
EBV primary infection
mononucleosis
mononucleosis symptoms
fever, pharyngitis, lymphadenopathy, splenomegaly,
atypical lymphocytosis
EBV reactivation
asymptomatic shedding
acute EBV tests for diagnosis
monospot positive
heterophile antibody positive (production of IgM)
EBNA negative
EBV tumors
B cell lymphoma
burkitts lymphona
nasopharyngeal carcinoma
prior EBV diagnosis
EBNA positive
CMV characteristics
worldwide
close contact/sex spread
CMV pathogenesis
primary infection of mucosa
latency in monocytes
reactivation and shedding
shedding of CMV blocked by
CD8 T cells
CMV symptoms
atypical lymphocytes
fever, pharyngitis
adenopathy
NO heterophile antibody
congenital disease of CMV
birth defects
deafness, vision impairment, developmental abnormalities
HHV-6 characteristics
in 90% of adults
acquire in childhood
spread by close contact
HHV-6 pathogenesis
spread by saliva
latent in T cell, monocytes, macrophages
reactivation is asymptomatic
HHV-6 symptoms
roseola- rash
fever
HHV-7
rarely cause disease
can cause roseola
HHV-8 characteristics
causes kaposi sarcoma
sexual transmission
seen in mediterranean men and men with AIDS
HHV-8 pathogenesis
infects B cells and endothelium
latency in B cells
shedding in saliva and semen
In immune suppressed
HHV-8 treatment
no vaccine
treat underlying immune deficiency
pox virus characteristics
largest human virus
enveloped
linear DNA
poxvirus types
orthopox
parapox
yatapox
molluscipox
orthopox causes
smallpox
molluscum contagiosum
spread by contact or fomite
painless skin nodules with virus inside
STI
