STI giant microbes

Sexually transmissible infections

Sexually transmissible infections (STIs) are infections which are passed from one person to another during unprotected sexual or genital to genital contact. STIs are caused by micro-organisms such as bacteria, viruses or parasites. STIs can affect areas of the body other than the genitals. They do not always cause signs or symptoms.

What activities can put you at risk of STIs?

Having vaginal or anal sex without a condom (called unprotected sex) can place you at risk of getting an STI. You can also get some STIs from unprotected oral sex, and from skin-to-skin contact.  Some activities put you at higher risk.

Riskier activities include having unprotected sex:

  • With casual partners (the more partners, the greater the risk).
  • With a partner who has had unprotected sex with casual partners.
  • When travelling outside Australia or with a partner who has had unprotected sex outside Australia.

Not everyone knows about safe sex from STIs

Safe sex does not just mean preventing unintended pregnancy. It is important to engage in safe sexual practices at all ages to protect yourself and your partner from contracting STIs.

Types of STIs

See ACTeenChoices: Sexually transmissible infections for comprehensive information about STIs.

For more information

ACTeenChoices: STIs

Sexual Health and Family Planning ACT: Health information brochures

Melbourne Sexual Health Centre

Australian STI Management Guidelines for Use in Primary Care

ASHM (Australasian Society of HIV, Viral Hepatitis and Sexual Health Medicine)

Family Planning NSW: STIs

Fact sheets