The causes of Warts are various types of human papillomavirus (HPV). Some types of HPV are also known to cause cancer of the cervix (mouth of the uterus).
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HPV infects the top layer of skin, usually entering the body in an area of broken skin. The virus causes the top layer of skin to grow rapidly, forming a wart. It can then spread from an existing wart to other areas of the body, causing more warts.