<unk> es are a diverse group of DNA-based viruses that infect the skin and mucous membranes of<unk> s and a variety of animals. Over 100 different<unk>  <unk>  types have been identified. Some<unk>  types may cause condylomas (skin warts) while others may cause a subclinical infection resulting in precancerous lesions.  All<unk> s are transmitted by skin-to-skin contact. A group of about 30-40<unk> s is typically transmitted through sexual contact and infect the anogenital region. Some sexually transmitted<unk> s -- types 6, 11,  may cause genital warts. However, other<unk>  types which may infect the genitals do not to cause any noticeable signs of infection.
Persistent infection with a subset of about 13 so-called "high-risk" sexually transmitted<unk> s, including types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68 — different from the ones that cause warts — may lead to the development of cervical intraepithelial neoplasia (CIN), vulvar intraepithelial neoplasia (VIN), penile intraepithelial neoplasia (PIN), and/or anal intraepithelial neoplasia (AIN).  These are precancerous lesions and can progress to invasive cancer. <unk>  infection is a necessary factor in the development of nearly all cases of cervical cancer.
Human papillomavirus
Cytomegalovirus
Human T-lymphotropic virus
Epstein Barr virus
Pomovirus
Herpes simplex virus
Parvovirus B19
Chlamydia trachomatis