Herpes Simplex

Basics

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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