Human Papillomavirus

Basics

Description

  • Members of the Papillomaviridae family, the human papillomaviruses (HPV), which cause warts of the skin and mucous membranes
    • Exophytic venereal warts or condylomata acuminata are primarily caused by HPV types 6 and 11.
    • Warts can be found on the external genitalia and the urethra, vagina, cervix, anus, and mouth. HPV types 6 and 11 are also associated with squamous cell carcinoma of the external genitalia.
    • Virus types 16, 18, 31, 33, and 35 typically cause subclinical infection in the anogenital region and have been associated with intraepithelial genital carcinomas.
  • HPV can also cause recurrent respiratory papillomatosis (RRP) in infants and young children. RRP primarily impacts the larynx but can also cause lesions anywhere along the respiratory tract.
  • Increasing evidence that HPV may play a role in squamous cell carcinomas of the oropharynx

Epidemiology

  • General
    • HPV is the most common viral sexually transmitted infection (STI).
    • Genital warts and HPV infection are diseases of young adults 16 to 25 years of age.
    • Cervical cancer is the 3rd most common female cancer worldwide.
  • Genital HPV
    • Peak prevalence among women 18 to 24 years of age
    • At least 40% of sexually active adolescents are infected with HPV.
    • <1% of adolescents develop genital warts.
    • 500,000 new cases of cervical cancer diagnosed each year internationally
  • RRP
    • RRP impacts 4.5 per 100,000 children, mostly those age 2 to 3 years.
    • 67% of children with RRP are born to mothers who had condyloma during pregnancy.

Risk Factors

  • Infants
    • Primarily vertical transmission at birth
  • Adolescents
    • Behavioral risks, including young age at first coitus, multiple partners, cigarette use, and having older male partners
    • Biologic risk in adolescent girls secondary to cervical anatomy

General Prevention

  • 9-valent HPV vaccine (HPV9 [types 6, 11, 16, 18, 31, 33, 45, 52, and 58]) is licensed by the FDA for use in females ages 9 through 26 years and in males ages 9 through 15 years. Condom use may diminish transmission.
  • Examine partners; treat those infected.
  • Pap smear in adult women to assess for cervical dysplasia
  • HPV infection is not a reportable disease.

Pathophysiology

  • Transmission
    • Primarily through sexual contact
    • Can also be acquired during the birth process
    • Transmission from nongenital sites is rare.
  • The incubation period is variable and ranges from 3 months to several years.
  • The virus is trophic for epithelial cells and infects the basal layer of actively dividing cells.
  • Infection results in koilocytosis and nuclear atypia. Genital infections may progress to severe dysplasia and carcinoma in situ (CIS).
  • Spontaneous regression of clinical disease occurs in 90% of low-risk types and 75% of high-risk types.
  • Recurrence is common.

Commonly Associated Conditions

  • Epidermodysplasia verruciformis
  • Other STIs

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