Papillomavirus (HPV)

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Viruses - DNA Viruses

Key Points

Human Papillomavirus (HPV)
- Characteristics
  - DNA virus
    - Replicates in nucleus
    - Double-stranded
  - No envelope
  - Circular chromosome
- Transmission
  - Sexually transmitted
    - Most common sexually transmitted disease
    - Barrier contraception (e.g. condoms) is protective
  - May also be spread through direct skin-to-skin contact
- Pathogenesis and Presentation
  - Warts
    - Serotypes 1, 2
      - Cutaneous warts
    - Serotypes 6,11
      - Condyloma acuminata (anogenital warts)
        Soft, tan, cauliflower-like masses on genitals
        Low oncogenic potential
      - Laryngeal warts
  - CIN/cervical cancer
    - Serotypes 16, 18, 31, 33 (over 16)
      - Also serotypes 35, 51
    - Viral oncogenes are integrated into host cell genomes
      - E6 degrades p53 protein (tumor suppressor)
      - E7 binds to Rb protein (tumor suppressor)
      - Immunosuppression (e.g. HIV) promotes oncogenesis by reducing immune monitoring
    - May cause other cancers (head and neck, anal, penile)
- Diagnosis
  - PCR is gold-standard
  - Pap smear may detect cervical lesions
- Treatment
  - Self-resolving
  - Cryotherapy (removal of warts), surgery/chemo for cancer
- Vaccination
  - Gardasil 9 in US
    - Targets 1,6, 16, 18, 31,33, 45, 52, 58
    - Used in young men/women (ages 9-26)