Human Papillomavirus
HPV
Human papillomavirus (HPV) is a group of DNA viruses that can infect many parts of the body. There are more than 100 different types of HPV; some of which infect the ano-genital area and are sexually transmitted, and others that infect other areas including the fingers, hands and face.
The cutaneous types of HPV, of which there are approximately 60 types, cause skin warts and are spread by skin-to-skin contact. Among the cutaneous types of HPV, approximately 40 types infect the epithelial cells of the genital mucosa, the remaining 20 types infect epithelial cells of anal or penile mucosa. Depending on the type of HPV that is acquired, infection can resolve without causing further complications, or can remain, progressing to cancer.
Some types of mucosal HPV are considered high risk types for their potential to cause cancer: for example, types 16 and 18 cause cervical cell abnormalities that can lead to cancer. Low risk types such as type 6 and 11 do not lead to cancer. Although these low risk types of HPV may cause cervical cell abnormalities, the abnormalities resolve and do not progress to cancer.
Infection with high risk types of HPV:
- is the cause of more than 99% of cervical cancer.
- is a major cause of anal cancer.
- may be responsible for cancers of the penis and throat.
High risk types of HPV that affect cervical cells may be active resulting in microscopic changes of cervical cells, or may be inactive resulting in a normal appearance of cells. Routine microscopic screening of cervical cells collected during a genital examination can detect microscopic changes that may be suggestive of cancer. The PAP smear, as it is commonly referred to, is named after the Papanicolaou stain that is applied to smears containing cervical cells to visualize their microscopic characteristics.
Genital HPV infection is often associated with the formation of genital warts, although HPV infection can be completely asymptomatic so that many people are not aware that they are infected. The types of HPV that cause genital warts do not cause cancer; however, it is possible to be infected with more than one type of HPV.
Genital warts (condylomata) are:
- flesh-coloured.
- soft to the touch.
- may resemble a small cauliflower or may be flat.
- often found in more than one location and may cluster in groups.
Genital warts are generally not painful, but may itch. In women, they appear on the vulva, cervix, rectum or inner thigh. In men, they appear on the penis, scrotum, rectum or inner thigh.
Sources:
Centers for Disease Control and Prevention (CDC)
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