ADENOVIRIDAE

• STRUCTURE: ds-DNA, linear, non-enveloped, enclosed in a cubical capsid. Capsomeres form hexons and pentons.

• REPLICATION: In nucleus.

  • The DNA has an accessory protein covalently linked at the 5' end, which aids in viral replication.

  • Early genes are transcribed in the cytoplasm. Early proteins inhibit host DNA synthesis and promote viral DNA synthesis and late gene expression.

  • Late genes transcribe a long mRNA that is differentially spliced to form structural proteins.

  • Replication differs from SV40 virus in that it proceeds from the ends toward the center, but there are no Okazaki fragments.

• ADENOVIRUS: 41 serotypes, grouped A-G.

  • PATHOGENESIS: Infects epithelial cells lining respiratory tract, GI tract, and conjunctiva.

    • It persists in lymphoid tissues such as Peyer's Patches may be reactivated in immunosuppression.

    • Produces a cytopathic effect (CPE) of grape-like clusters in culture.

  • TRANSMISSION: Fecal-oral, respiratory.

  • MANIFESTATIONS: Only a small number of infections.

    • Acute Respiratory Infections: Types 4-7. Military recruits now get a vaccine to prevent this.

    • Conjunctivitis: Types 3 and 8. Epidemic keratoconjunctivitis or Shipyard-Eye.

    • Acute Gastroenteritis: Types 40 and 41, especially in infants.

    • Acute Hemorrhagic Cystitis: Young males; types 11 and 22.

    • Cervicitis and urethritis: Types 37

    • Pharyngoconjunctival fever: In children, types 3 and 7

    • Acute febrile pharyngitis

Category: Microbiology Notes