ODR

How are HSV, VZV, and Variola spread?
HSV: direct contact
VZV: respiratory route
variola: respiratory or contact
Cowdry’s Type A Acidophilic intranuclear inclusion bodies
HSV
Tzanck Smear
HSV
see multinucleate giant cells
Where does the HSV replicate?
in vesicular lesions
What is the immune response against HSV?
ABs against glycoproteins to neutralize/limit the spread of EC virus
CMI: essential for controlling & resolving the infection
mutlinucleate giant cells
HSV
What is the pathogenesis of VZV?
replication in respiratory tract
viremia: blood & lymph to reticuloendothelial cells
skin lesions on entire body: dermal vesciulopapular rash, develops in successive crops
becomes latent in DR or CN ganglia
How is HSV treated?
1st herpes episode: acyclovir (oral or topical)
What is the incubation period of VZV?
14 days
dew drop on rose petal
VZV
successive crops with lesions in all different stages
VZV
unilateral lesions in a dermatome
Herpes Zoster
postherpetic neuralgia (chronic pain syndrome)
can develop from herpes zoster
How is VZV treated?
vaccine: live, attenuated
adults/immunocomp: acyclovir
What is the largest, most complex dsDNA virus?
variola/small pox
Guarnieri bodies
variola
What is special about the variola virus compared to other DNA viruses?
It replicates in the cytoplasm instead of the nucleus
What are the 2 variola viruses that infect humans?
orthopox virus (small pox)
molluscipox vireus (molluscum contagiousum)
wart-like growth in clusters
molluscum contagiousum
hemorrhage of small BVs
orthopox virus (small pox)
rash starts on face/extremities and spreads inward
small pox
Which human virus of variola can lead to death?
orthopoxvirus: can lead to death
molluscipoxvirus: benign/self-limiting
slapped-cheek rash
parvovirus B19
ssRNA (-) sense virus
measles
How is measles transmitted?
respiratory droplets
contagious 1-2 days before and up to 4 days after the rash
90% attack rate, 100% symptomatic
What are the virulence factors of measles?
HN: viral attachment
F: fusion of cells/viral entry
M: inside viral envelope; important in viral assembly
cough, coryza, conjuctivitis, fever, Kaplik’s spots
Measles
What are some complications of measles?
bacterial superinfection
post-infectious meningo-encephalitis
SSPE
progressive infectious encephalitis
giant cell PNA w/rash
ssRNA (-) sense virus
rubeola
What is the clinical presentation of Rubeola Virus?
Cough, Coryza, Conjuctivitis, Kalik’s spots, maculopapular rash that lasts for 5 days
cough, coryza, conjuctivitis, kaplik’s spots, maculopap rash
rubeola vrius
How is Rubeola Virus spread?
respiratory droplets
contagious 1-2 days before and up to 4 days after rash
peaks in winter & spring
Explain the pathogenesis of Rubeola Virus
1. HN: viral attachment
2. F: fusion of cells/viral entry
3. M: important in viral assembly inside envelope
4. 7-21 day incubation
5. local replication in respiratory epithelium
6. lymph spread
7. viremia
5. systemic infection
6. immune response/maculopap rash
7. complications: PNA, post-infectious encephalitis, subacute sclerosing panencephalopathy
What virus does not replicate in the respiratory epithelium?
HSV
What are some complications of Rubeola Virus?
bact. superinfection i.e. PNA
post-infectious meningo-encephalitis
SSPE caused by defective virus assembly
progressive infectous enceph (2-10yrs after primary infection)
giant cell PNA w/rash
When is the MMR vaccine administered?
12-15 months and a booster during elementary school
What age group is most affected by Parvovirus B19?
ages 4-15
How is parvovirus B19 spread?
resp secretions and parenteral transmission
What virus replicates in mitotically active cells of erythyroid origin?
parvovirus B19
slapped-cheek rash
parvovirus B19
What are the 2 phases in fifth disease?
1. flu-like Sxs
2. slapped-cheek rash, arthralgias
Who is at risk for complications from parvovirus B19?
chronic anemia: risk for aplastic crisis
seronegative women: at risk for fetal loss
immunocomp: progressive BM suppression
naked DNA virus
parvovirus B19
How is roseola spread?
saliva and respiratory aerosols
In what age group is Roseola most common?
<4 years old
What is the clinical presentation of Roseola (Human Herpesvirus-6)?
high fever, maculopapular rash seen in AIDS patients and children <4
syncytia formation/multinucleate giant cells
rubeola virus
ssDNA virus
parvovirus B19
Categories: Microbiology