Candidiasis, thrush, or yeast infection is a fungal infection of any species from the genus Candida. Candida albicans is the most common agent of candidiasis in humans. It is also technically known as candidosis, moniliasis, and oidiomycosis. Candidiasis encompasses infections that range from superficial, such as oral thrush and vaginitis, to systemic and potentially life-threatening diseases. Candida infections of the latter category are also referred to as candidemia or invasive candidiasis, and are usually confined to severely immunocompromised persons, such as cancer, transplant, and AIDS patients, as well as nontrauma emergency surgery patients.