In August 2025, syphilis was declared a Communicable Disease Incident of National Significance (CDINS) in Australia.
The sexually transmitted infection (STI) is caused by the bacterium Treponema pallidum and affects people of all genders, ages and backgrounds.
Syphilis can be serious if left untreated and often shows no symptoms – meaning it requires a proactive and vigilant approach to screening, testing, education and treatment.
Prevention and spread
Syphilis is mainly spread through unprotected vaginal, anal or oral sex with someone who has an infection. It can also be passed from a pregnant person to their child during pregnancy or birth, which can cause severe complications.
Recent years have seen an increase in syphilis cases in Victoria and New South Wales, particularly among gay, bisexual and other men who have sex with men, as well as women of reproductive age. Routine testing and community awareness are essential to reversing this trend.
Protection strategies include using condoms and dental dams during sex, regular STI checks especially for people who have new or multiple partners.
Notifiable infectious disease
Syphilis is a nationally notifiable disease and cases are monitored through the National Notifiable Diseases Surveillance System (NNDSS) and data is reported quarterly national syphilis monitoring reports.
For more information and guidance for health professionals visit the Australian Centre for Disease Control.
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