Candidiasis is a fungal infection caused by a yeast (a type of fungus) called Candida. Some species of Candida can cause infection in people; the most common is Candida albicans. Candida normally lives on skin and inside the body, such as the mouth, throat, gut, and vagina, without causing problems.Fungal infections come in different forms, like ringworm athlete's foot, toenail fungus, yeast infections, and jock itch.