Candidiasis (also called yeast infection or thrush) and bacterial vaginosis are the most common vaginal infections and they are usually due to an overgrowth of organisms normally present in the vagina. They may or may not be sexually transmitted. Candidiasis (which can cause curd-like discharge and itchiness) is not usually sexually transmitted. Research links bacterial vaginosis with sexual behavior. Women with multiple partners are more likely to have bacterial vaginosis, but even a woman who has never had sex can, rarely, develop bacterial vaginosis.

• In most settings these infections are much more common than STIs. Researchers estimate that between 5% and 25% of women have bacterial vaginosis, and between 5% and 15% have candidiasis, at any given time. 
• Vaginal discharge due to these infections may be similar to discharge caused by some STIs; the discharge caused by bacterial vaginosis, for example, is similar to that caused by trichomoniasis. It is important to explain to clients with vaginal discharge that they may not have an STI, particularly if they do not have any other symptoms and are at low risk of a STI.
• Bacterial vaginosis can be cured with antibiotics, usually metronidazole. Candidiasis can be cured with antifungal medications such as fluconazole. Without treatment, bacterial vaginosis can sometimes lead to complications in pregnancy, and candidiasis can be spread to an infant during childbirth.

Good hygiene may help some clients avoid vaginal infections. Washing the external genital area with unscented soap and clean water, and not using douches, detergents, disinfectants, or vaginal cleaning or drying agents, are good hygiene practices.