Causes of syphilis
Syphilis is usually spread through skin-to-skin contact during vaginal, anal, or oral sex. However it can also be spread by kissing or by direct contact with open sores on areas such as the lips, mouth, breasts, or genitals.
Syphilis is highly infectious during the time when a sore or rash is present. It can also be passed on during the early part of the latent stage and by people who don't have any symptoms of infection.
Syphilis can occasionally be spread by blood contamination, via needle-stick injury or sharing injecting equipment. However it is very rare to get syphilis through a blood transfusion.
A pregnant woman with syphilis can pass the infection on to her baby via the placenta during pregnancy.
Your doctor will need to do a blood test to confirm a diagnosis of syphilis. However, if your result is negative, you will need to be re-tested, because it can take three months to develop antibodies. Your doctor may also do a swab test from a sore. When syphilis is diagnosed your doctor will report it to the local health authorities.
A positive blood test in a person without symptoms is the most common way people find out they have syphilis in Australia today.
Last reviewed: June 2015