Transmission
Human papillomavirus (HPV) infection occurs as a result of skin-to-skin contact. The virus typically is best able to spread when it is causing symptoms (i.e. warts or other skin lesions). After skin-to-skin contact, human papillomavirus enters into the body by invading cuts and abrasions on the skin, even if these breaks in the skin are too small to be visible. Human papillomavirus is also classified as a sexually transmitted disease because it can be spread as a result of anal, vaginal or oral sex. In some cases, HPV that is spread from oral sex can also infect the respiratory system.
Infection
The human papillomavirus follows the typical life cycle of most viruses. Once the virus comes into contact with an uninfected host, it enters into the cell. Viruses are mostly made out of genetic material, such as DNA or RNA. Once a virus enters a cell, it utilizes the cell's infrastructure for DNA replication to make more copies of the virus and viral proteins. The human papillomavirus will make many copies of itself until it has exhausted the cell's resources. Then it will leave the cell and infect nearby cells. Sometimes the virus can lie dormant within cells for long periods of time in order to avoid detection by the immune system.
Types
There are more than 100 different strains of human papillomavirus. Although different strains cause infections in different areas of the body, overall the human papillomavirus causes warts to appear. These warts may appear on the genitals, the hands, the feet, in the mouth or on other areas of the body (such as the neck, wrists and elbows). HPV infections are fairly common and infected people are most contagious when they actually have warts. During this period of time the virus is actively replicating and spreads more easily, although sometimes these infectious lesions are too small to be seen by the naked eye.
