Thrush. Woman's vagina showing a white discharge due to thrush (or candidiasis or moniliasis). This is due to an infection with the yeast-like fungus Candida albicans. This fungus is normally present in the vagina and mouth, but the presence of bacteria in these areas inhibits its growth. The population of C. albicans may increase dramatically if the bacteria die as a result of a course of antibiotics, or if the patient has a weakened immune system. Thrush may also be contracted through sexual intercourse with an infected partner. It may cause irritation and itching as well as a discharge, although some people have no symptoms. It can be treated with antifungal drugs.