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34 Cards in this Set
- Front
- Back
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What is special about poxviruses?
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Largest and most complex viruses (brick-shaped, enveloped)
They are dsDNA virus that replicates in the cytoplasm |
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What are some examples of poxviruses?
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Orthopox = Variola (small pox)
Vaccinia Monkeypox, cowpox Parapoxviruses = Orf Milker's nodule Yatapox Molluscipox |
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What is Variola?
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Causes smallpox
Last reported case 1977 only infects humans - one serotype |
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What is Vaccinia?
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Source of smallpox vaccine
Very large genome can be used in gene therapy (also for herpes vaccine trials) Similar to cowpox (milkmaids) |
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Why is CMI and humoral necessary to resolve pox infection?
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Large genome encodes immune escape mechanisms
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How are poxviruses spread?
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Transmitted via respiratory route.
Most are infections by accidental exposure Molluscipox spread by direct contact |
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What is the pathophysiology of smallpox infection?
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Inhaled and replicates in upper respiratory tract
Vesicles form 4 days after onset of flu-like symptoms Death in some cases due to overwhelming viral infection and bacterial superinfection |
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What was the first disease controlled by a vaccine?
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Smallpox.
Scar indicated successful vaccination |
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What is the pathophysiology of Orf, cowpox, monkeypox?
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Nodular lesions on finger & face
--> spontaneous resolution |
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What is the pathophysiology of molluscipox (molluscum contagiosum)?
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Nodular, painless lesions on skin
No systemic symptoms --> spontaneous resolution |
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How do you diagnose molluscipox?
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Diagnosed by the presence of eosinophilic cytoplasmic inclusions in affected tissue
--> called moluscum bodies |
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Inclusion bodies that form in the cytoplasm during pox replication are called ______?
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Guarneri bodies
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What are some examples of papovaviruses? What is their genome?
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Polyomaviruses
Papillomaviruses dsDNA - circular - Naked (vs. pox = dsDNA - linear -env) |
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What are some examples of polyomaviruses?
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SV-40 in primates
JC virus and BK virus |
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What are some special characteristics of polyomaviruses?
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SMall, naked viruses that can transform heterologous cells in culture
SV-40 used as model for tumor viruses |
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What is the epidemiology of polyomaviruses?
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Ubiquitous
--> usually do not cause apparent disease |
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What is the pathophys of JC virus?
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Found in immunosuppressed adult's urinary tract (AIDS, RES malignancies)
- can cause progressive multifocal leukoencephalopathy (PML) = fatal CNS demyelinating disease - viral damage to oligodendrocytes |
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What is the pathophys of BK virus?
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Found in urinary tract of immunocomp
ex. kidney transplant - associated with hemorrhagic cystitis in bone marrow transplant recipients |
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How is polyomavirus diagnosed?
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BK = routine cell culture
JC = requires fetal glial cells Ag detection by immunoassay |
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What are characteristics of papillomavirus?
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small, naked
dsDNA - circular **Wide genomic diversity - over 70 genotypes Replication tightly linked to cellular differentiation |
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What cells do papillomavirus target?
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Epithelial and keratinocytes
= replication dep on epithelial differentiation stage |
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How is papilloma virus spread?
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Ubiquitous - aquired by close contact
- infects many vertebrate species but is highly species-specific |
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What are some clinical manifestations of papillomavirus?
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Genital warts
Common warts epithelial/epidermal papillomas squamous cell carcinomas |
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What determines the type of clinical manifestation?
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Dependent on the genotype
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What does the virus produce to control cell growth and differentiation?
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Produces viral oncoproteins: E6 and E7
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What is the mode of action by E6?
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E6 keeps p53 levels very low by targeting it for ubiquination and degradation.
- normally p53 will increase to high levels during viral infection or DNA damage/cell stress and cause arrest of cell cycle @ G1 |
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What is the mode of action for E7?
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E7 binds Rb and histone deacetylase-1
-when Rb binds E7, it can no longer bind E2F -unbound E2F is transcriptionally active |
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What can happen when papillomavirus integrates into host genome?
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Can result in unregulated expression of E6 and E7
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How do you diagnose papillomavirus?
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Perinuclear cytoplasmic vacuolization and nuclear enlargement (koilocytosis) in epithelial cells
--> can be seen in PAP smear or tissue section Immunoassays for viral Ag Cannot culture virus Usually use detection of viral DNA -PCR, ISH, Southern blot |
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What is therapy and prevention for HPV?
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Vaccine for types 6, 11, 16. 18
Removal of lesions IFN Antisense RNA Condoms |
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HPV 6, 11, 16 and 18 cause ??
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Mucosal/gential warts
- 6 & 11 --> 90% of genital wars and low risk association with cancer - 16 & 18 --> 70% of cervical cancers and high risk |
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HPV 1, 2 and 4 cause ??
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cutaneous warts
numerous EV-associated diseases immunocomp; are some high risk types assoc with skin cancers |
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What is focal epithelial hyperplasia?
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Found in mouth and genitals caused by HPV 13 and 32
- called "Heck's Disease" - familial |
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True or False.
HPV positive oral cancers have a better prognosis. |
True.
Usually caused by HPV 16 and 18 |
