What kind of virus causes warts?

Warts are caused by the human papillomavirus (HPV), which is a group of over 200 related viruses. Specific strains of HPV are responsible for different types of warts, such as common warts, plantar warts, and genital warts. The virus infects the skin's top layer, leading to the growth of benign tumors that appear as warts. Transmission typically occurs through direct skin-to-skin contact or by touching surfaces contaminated with the virus.