- Adenovirus, parvovirus, and polyomavirus are DNA viruses that cause respiratory illnesses and other diseases. - Adenovirus has a medium sized dsDNA genome and causes respiratory illness, conjunctivitis, and gastroenteritis. Parvovirus has a small ssDNA genome and targets erythroid cells, causing fifth disease. Polyomavirus has a small dsDNA genome and establishes kidney persistence, with potential reactivation and progression to PML. - The viruses replicate in the nucleus and spread locally or via viremia. Immunity is important for control of adenovirus and parvovirus.

1. Adenovirus, parvovirus,
polyomavirus

2. Adenovirus

3. From Medical Microbiology, 5th
ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 53-1.
Adenovirus Structure

4. E1
E2 E4
E3
Late genes
Adenovirus Genome
36 kb linear ds DNA
Early genes for host and viral transcription control,
viral DNA replication
Late genes for virion structure

5. (From Fields Virology, 4th ed, Knipe & Howley, eds, Lippincott Williams & Wilkins, 2001, Fig. 67-5.)
Adenovirus replication cycle

6. From Medical Microbiology, 5th
ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Table 53-1.
Adenovirus diseases

7. From Medical Microbiology, 5th
ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005,, Fig. 50-4.
Adenovirus pathogenesis

8. 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

9. Parvovirus

10. Parvovirus structure
From Medical Microbiology, 4th
ed., Murray, Rosenthal, Kobayashi & Pfaller, Mosby Inc., 2002, Fig. 53-1.

11. Parvovirus Genome
Rep Cap
5 kb ssDNA, inverted terminal repeats (ITR)
Rep gene required for DNA replication
Cap gene encodes capsid proteins
ITR ITR

12. Autonomous parvovirus replication
Postulated replication of parvovirus (B19) based on
information from related viruses (minute virus of
mice). The internalized parvovirus delivers its
genome to the nucleus, where the single-stranded
(plus or minus) DNA is converted to double-stranded
DNA by host factors and DNA polymerases present
only in growing cells. Transcription, replication, and
assembly occur in the nucleus. Virus is released by
cell lysis.(From Medical Microbiology, 5th
ed., Murray,
Rosenthal, Kobayashi & Pfaller, Mosby Inc., 2002,
Fig. 56-2.)

13. Helper dependent parvovirus (AAV) replication
AAV DNA
integrates into
chromosome 19
Infection without adenovirus
Infection with adenovirus
Superinfect
with
adenovirus
Lytic
replication

14. A "slapped-cheek" appearance is typical of the rash for erythema infectiosum.(From Medical
Microbiology, 5th
ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 56-5.)
Parvovirus pathogenesis

15. From Medical Microbiology, 5th
ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig. 56-3.
Parvovirus pathogenesis

16. 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

17. Polyomavirus

19. Polyomavirus genome
Genome of the SV40 virus. The genome
is a prototype of other polyomaviruses
and contains early, late, and noncoding
regions. The noncoding region contains
the start sequence for the early and late
genes and for DNA replication (ori). The
individual early and late messenger RNAs
are processed from the larger nested
transcripts.(From Medical Microbiology,
5th
ed., Murray, Rosenthal & Pfaller,
Mosby Inc., 2005, Fig. 52-7.)

20. 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. (From
Fields Virology, 4th ed, Knipe & Howley, eds, Lippincott Williams & Wilkins, 2001, Fig. 63-4.)
Polyomavirus replication

21. From Medical Microbiology, 5th
ed., Murray, Rosenthal & Pfaller, Mosby Inc., 2005, Fig.52-8.
Polyomavirus pathogenesis

22. 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 ?