HPV (human papillomavirus) infection is caused by a group of viruses with more than 100 subtypes. More than 40 subtypes have been implicated in human infections affecting the genital regions. There has been further classification of these viruses into low-risk and high-risk groups. The low-risk group causes proliferation of skin cells into warts, which can be seen around the genitals or anus. The high-risk group is implicated in cancers involving the cervix, vulva, vagina, anus and penis.
There are an estimated 20 million people living with this virus, with more than 6 million new cases every year, according to a 2007 report by the Centers for Disease Control (CDC). Estimates put the number of new cases of cervical cancer at about 11,000 and cancers involving other male and female genitalia at 12,000 new cases each year, according to the CDC.
HPV is usually cleared by a healthy immune system, but it will linger in the body in some cases, putting the person at risk for malignant developments. It is out of control in the presence of deficiencies of the immune system, as seen in HIV/AIDS.
How HPV Is Transmitted
HPV makes its home within the layers of the skin, where it expresses its presence by altering the normal behavior of the skin cells. The presence of HPV can usually go unnoticed until the clinical manifestations of warts or cancerous change. Thus, it can be transferred from apparently normal skin during sexual intercourse. Friction and old wounds, such as from previous sexually transmitted diseases, encourage this transfer. The fact that it is transferred from skin to skin means that there is very limited protection offered by latex condoms, since this covers only a little surface area of contact.
Once in contact with skin, HPV makes its way to the basal layers, where cell division takes place to replenish the layers of skin cells. This is where it resides, sometimes for years, before clinical manifestation or being cleared by the body's defense mechanisms.
Those at Fisk for HPV
The presence of skin lesions and cuts, sometimes from shaving or improper tampon use, greatly increases transfer of the virus. Having multiple sexual partners is another high-risk factor. A compromised immune status, genetic or acquired, such as HIV/AIDS, also increases transfer. For some not so clear reasons, pregnancy and cigarette smoking also increase the risks.
Recent vaccine development against the virus offer some hope of control. It is recommended for pre-teenage girls.
