Herpes, Genital

Description

• Genital herpes is a lifelong recurrent infection
• Two types of HSV can cause genital herpes: HSV-1 and HSV-2
• Most cases of recurrent genital herpes are caused by HSV-2
• There is an increasing proportion of HSV-1 anogenital herpetic infections
• ∼50 million persons in the U.S. are infected with HSV-2
• Most reported cases involve the age groups between 16–40 yr
• Genital herpes simplex virus (HSV) infections are designated as primary, nonprimary first episode, recurrent, asymptomatic
• Primary HSV infection:
  • Refers to infection in a patient without preexisting antibodies to HSV-1 or HSV-2
  • Average incubation period after exposure is 4 d (range 2–12 d)
• Nonprimary first episode:
  • Refers to acquisition of genital HSV-1 in a patient with preexisting antibodies to HSV-2 or vice versa
  • Associated with fewer lesions and less symptoms than primary infection
  • Antibodies against one HSV type offer some protection against the other
• Recurrent HSV infection:
  • Refers to reactivation of genital HSV in which the HSV type recovered in the lesion is the same type as antibodies in the serum
  • Duration of lesions is shorter than with primary infection (10 vs. 19 d)
  • Symptoms can be less severe; genital lesions may be asymptomatic, fewer in number, atypical in appearance
  • Duration of viral shedding is shorter than primary infection (2 vs. 9 d)
• Asymptomatic HSV infection:
  • Virus is shed intermittently and often transmitted by persons who are without lesions or symptoms
  • Asymptomatic shedding of HSV from the genital tract is most common source of transmission of infection

Etiology

• 70–90% caused by a DNA virus HSV-2:
  • Remainder caused by HSV-1
• Infection with HSV-1 generally occurs in the oropharyngeal mucosa:
  • Trigeminal ganglion becomes colonized; harbors latent virus
  • Increasingly more common to detect evidence of HSV-1 in the genital tract, usually due to oral–genital sex
  • Recurrences of HSV-1 in the genital tract uncommon
• Acquisition of HSV-2 infection is usually the consequence of transmission by genital contact:
  • Virus replicates in the genital, perigenital, or anal skin sites:
    • Latent virus in sacral ganglia
  • HSV-2 can also infect the mouth:
    • Recurrences at this site uncommon
• HSV vaccines unsuccessful to date, research is ongoing
• High association with HIV and other STDs

• Contact isolation and universal precautions should be maintained
• Those infected with HSV-2 are 2–3 times more likely to acquire HIV:
  • Patients who test positive for HSV-2 should also be tested for HIV