Herpes Simplex



  • Viral disease characterized by recurrent painful vesicular lesions of mucocutaneous areas
  • Lips, genitalia, rectum, hands, and eyes most commonly involved
  • Infection is characterized by 2 phases:
    • Primary, virus established in a nerve ganglion
    • Secondary, recurrence of disease at the same site
  • Incubation period is ∼4 d from exposure
  • Viral shedding occurs from 7–10 d (up to 23 d) in primary infection and 3–4 d in recurrent infections
  • Neonatal infections can occur in utero, intrapartum (most common), or postnatal
    • Occur in 1/3,500 births per year in the U.S.
  • Human-to-human transmission
  • HSV-1 – one of the most common viral causes of encephalitis in the U.S.
    • Untreated infection with mortality rate >70%
  • HSV-1 usually from childhood through nonsexual contact
  • HSV-2 almost always sexually transmitted
  • 60–90% of population is infected with herpes simplex type 1 (HSV-1) or type 2 (HSV-2)
  • More common in blacks than whites in ages <40 yr
  • Females affected more than males


  • HSV-1 or HSV-2 are DNA viruses of the Herpesviridae family
  • Viral transmission may occur via respiratory droplets, contact with mucosa or abraded skin with infected secretions: saliva, vesicle fluid, semen, cervical fluid:
    • Recurrent mucosal shedding of HSV may transmit the virus
    • Rate of recurrence varies with virus type and anatomic site
  • Both viruses infect oral or genital mucosa:
    • Most common for HSV-1 to cause oral infections and HSV-2 to cause genital infections
  • Herpes Simplex Encephalitis: Access via olfactory or the trigeminal nerve:
    • Prefers medial and inferior temporal lobes

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