Adenovirus, parvovirus,
polyomavirus
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Adenovirus
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Adenovirus Structure
From Medical Microbiology, 5th ed.,
Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 53-1.
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Adenovirus Genome
Late genes
E1
E2
E3
E4
36 kb linear ds DNA
Early genes for host and viral transcription control,
viral DNA replication
Late genes for virion structure
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Adenovirus replication cycle
(From Fields Virology, 4th ed, Knipe & Howley, eds, Lippincott Williams & Wilkins, 2001, Fig. 67-5.)
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Adenovirus diseases
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Adenovirus pathogenesis
From Medical Microbiology, 5th ed.,
Murray, Rosenthal & Pfaller, Mosby Inc., 2005,, Fig. 50-4.
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Summary: adenovirus
• Structure
– Medium sized (36 kb) dsDNA genome, naked capsid
• Pathogenesis
–
–
–
–
respiratory or fecal oral transmission
replication in nucleus; moderately host dependent
local spread; viremia
cellular and humoral immunity important; virus encodes
countermeasures against MHC I expression and apoptosis
– direct cell damage from replication; respiratory illness,
conjunctivitis, gastroenteritis, cystitis
• Diagnosis
– culture, viral antigen detection
• Treatment/prevention
– live military vaccine
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Parvovirus
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Parvovirus structure
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Parvovirus Genome
ITR
ITR
Rep
Cap
5 kb ssDNA, inverted terminal repeats (ITR)
Rep gene required for DNA replication
Cap gene encodes capsid proteins
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Autonomous parvovirus replication
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Helper dependent parvovirus (AAV) replication
Infection with adenovirus
Infection without adenovirus
Lytic
replication
AAV DNA
integrates into
chromosome 19
Superinfect
with
adenovirus
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Parvovirus pathogenesis
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Parvovirus pathogenesis
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Parvovirus
• Structure
– Small (5 kb) linear ssDNA genome, naked capsid
• Pathogenesis
– respiratory transmission
– replication in nucleus, very host dependent, needs S phase
cells or helper virus
– viremia
– antibody important in immunity
– targets erythroid lineage cells; fifth disease (symptoms
immunological); transient aplastic crisis; hydrops fetalis
• Diagnosis
– serology, viral nucleic acid
• Treatment/prevention
– none
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Polyomavirus
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Polyomavirus genome
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Polyomavirus replication
Replication cycle of polyomaviruses. Steps in the replication cycle are indicated by numbers as follows: 1, adsorption of virions to
the cell surface; 2, entry by endocytosis; 3, transport to the cell nucleus (route and mechanism not yet known); 4, uncoating; 5,
transcription to produce early region mRNAs; 6, translation to produce early proteins (T antigens); 7, viral DNA replication; 8,
transcription to produce late region mRNAs; 9, translation to produce late proteins (capsid proteins); 10, assembly of progeny
virions in the nucleus; 11, entry of virions into cytoplasmic vesicles (mechanism unknown); 12, release of virions from the cell by
fusion of membrane vesicles with the plasma membrane; 13, released virion.
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Polyomavirus pathogenesis
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Polyomavirus
• Structure
– Small (5 kb) circular dsDNA genome, naked capsid
• Pathogenesis
–
–
–
–
respiratory transmission
replication in nucleus; very host dependent
viremia
persistence in kidneys; reactivation with immune
compromise
– inapparent infection; hemorrhagic cystitis; PML
• Diagnosis
– viral nucleic acid
• Treatment/prevention
– cidofovir ?
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