Herpes Simplex

Basics

Description

  • Viral disease characterized by recurrent, self-limited, painful vesicular lesions of mucocutaneous areas
  • Leads to genital infections as well as orolabial, skin, ocular, and CNS manifestations
  • Severe complications include encephalitis, neonatal herpes, and fatal dissemination especially in immunocompromised hosts
  • Caused by herpes simplex type-1 (HSV-1) or type 2 (HSV-2)
  • Infection is characterized by 2 phases:
    • Primary – virus established in a nerve ganglion which is often asymptomatic
    • Nonprimary – acquisition of HSV by person already infected with other subtype
    • Secondary – latent infection in patient with preexisting immunity
  • Worldwide, HSV-1 has 50–80% seroprevalence and HSV-2 10–15%, higher in women and non-Hispanic African American populations
  • HSV-2 infections increase susceptibility to HIV infection
  • HSV reactivation associated with nearly 80% of recurrent erythema multiforme cases
  • HSV-1 is one of the most common viral causes of encephalitis in the US:
    • Untreated infection with mortality rate >70%

Etiology

  • HSV-1 and HSV-2 are DNA viruses of the Herpesviridae family
  • Establishes latency in neural ganglia after primary infection and reactivates to cause recurrent infection or subclinical viral shedding
  • Both HSV-1 and HSV-2 transmitted through intimate contact of skin and mucosal surfaces:
    • HSV-1 typically transmitted by oral secretions and nonsexual contact and involves oral, pharyngeal, facial, ocular, and CNS infections
    • HSV-2 typically involves anogenital tract and transmitted mainly through sexual contact
  • Incubation period is ∼4–10 d from exposure
  • Viral shedding occurs from 7–12 d (up to 23 d) in primary infection and 3–4 d in recurrent infections

There's more to see -- the rest of this topic is available only to subscribers.