What Is It?
Warts are small skin growths caused by the human papilloma virus (HPV), which infects the top layer of skin. There are more than 40 different types of HPV. The wart virus can be transmitted from one person to another either by direct contact, or indirectly when both people come in contact with a surface, such as a floor or desk.
People may come into contact with HPV by walking barefoot in public places, such as gyms and shower floors or by sexual contact. HPV also can be transmitted in the same person from one spot on the body to another. It is easier for HPV to infect a person when the person's skin is scratched or cut.