What techniques are used to study warts?

HPV infection occurs after exposure to humans or animals with HPV infection. The most common mode of transmission is through touch or contact from an individual infected with HPV, although HPV may also survive on inanimate objects for unknown amounts of time. Small abrasions or cracks in the skin of exposed persons allow the virus to penetrate. Such infection may commonly occur at a swimming pool, where chlorinated water and rough concrete surfaces may abrade the skin, or at other public places. Genital warts may be transmitted through sexual intercourse. People who work with meat, fish, and poultry also commonly have warts in the hand and forearm area, which are thought to be promoted through microinjuries sustained during processing of animals or fish, as well as from prolonged immersion of the skin in water.

Autoinoculation is another form of transmission. Periungual warts are often found in persons who have a habit of biting their cuticles, for example. Presumably the excoriated areas are more hospitable to virus, but spread of a single common wart is also possible. Flat warts in the beard area or on the legs may be spread by shaving.