Adenovirus: Grupo de virus que causa resfriados, neumonía, conjuntivitis y gastroenteritis en humanos. Se propaga a través de gotas respiratorias y contacto cercano. Parvovirus: Familia de virus que afecta a humanos y animales. Parvovirus B19 causa la quinta enfermedad en humanos, caracterizada por una erupción en las mejillas. Otros parvovirus afectan a perros y gatos. Polyomavirus: Pequeños virus de ADN que pueden infectar humanos y causar enfermedades como la leucoencefalopatía multifocal progresiva (PML) en personas con sistemas inmunológicos debilitados, y infecciones renales en receptores de trasplantes. Se encuentran comúnmente en la población general.

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
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. 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
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 ?