What is syphilis?
Syphilis is a sexually transmissible infection of clinical significance to Australian travellers. It is caused by Treponema pallidum, a spiral shaped bacterium. The organism itself is highly specific in its behaviour, solely affecting humans as opposed to other species.
Transmission occurs through the penetration of the bacterium through mucosal membranes and small abrasions on the surface of the skin. It is primarily spread through sexual contact, although it can also be transmitted through exposure to infected blood products and passed from a pregnant woman to her unborn child. The infection progresses through four recognised stages, primary, secondary, latent, and tertiary, with the clinical picture changing considerably as the disease advances. Syphilis can present in a wide variety of ways and is capable of mimicking many other infections and immune related conditions, particularly in its later stages.
Given that syphilis has been formally declared a Communicable Disease Incident of National Significance by Australia's Chief Medical Officer, awareness of transmission risk is relevant for any Australian traveller engaging in sexual activity overseas, particularly with new or casual partners.
FAQs
How can I catch syphilis while travelling?
+
Sexual contact remains the primary route of transmission, but it is not the only one. Syphilis can also be transmitted from mother to fetus during pregnancy, through blood product transfusion, and occasionally through breaks in the skin that come into contact with infectious lesions. For most travellers, the practical risk relates almost entirely to sexual contact, including oral sex, so this remains the focus of prevention advice for those travelling overseas.
Could I still have syphilis if I don't have symptoms?
+
Yes. Some people with syphilis have no symptoms at all, meaning a person may not know they are infected unless they are specifically tested. Symptoms of primary and secondary syphilis can also be mild and easily go unnoticed, and the infection can later progress to a stage with no visible signs whatsoever. This is particularly relevant for travellers who have had a new sexual partner overseas, even where no symptoms developed afterwards.
If I was treated for syphilis previously, am I protected if I am exposed again while travelling?
+
No. Previous treatment and recovery from syphilis does not provide immunity, and reinfection can occur. Travellers who have a history of syphilis should continue to practise the same preventive measures as anyone else and should seek testing again if they believe they may have been exposed during a trip.
What should I do when I get home if I think I have been exposed during travel?
+
You should arrange testing with a doctor or sexual health clinic as soon as practical after returning to Australia, even in the absence of any symptoms.
Diagnostic tests for syphilis are highly effective, and timely antibiotic treatment cures the infection and prevents further transmission to others. If you have had a new sexual partner while overseas, it is also worth requesting a broader sexual health check, as other sexually transmissible infections can be acquired at the same time.
What to Know
Syphilis symptoms
The symptoms of syphilis vary considerably depending on the stage of infection, and the disease can be difficult to recognise without specific testing.
In the primary stage, a single painless sore (chancre) usually appears at the site of infection about 10 to 90 days after exposure, most often around three weeks. This may occur on the genitals, anus/rectum, or mouth. The sore is typically firm, round, and painless, so it is often unnoticed, and it heals on its own within a few weeks even without treatment.
If untreated, the infection progresses to the secondary stage, usually 2 to 24 weeks after the sore resolves. This may cause a non-itchy rash on the trunk, palms, and soles, along with flu-like symptoms such as fever, swollen lymph nodes, patchy hair loss, and sometimes lesions in the mouth or genital/anal area. These symptoms also tend to resolve without treatment, but the infection remains in the body.
The infection then enters a latent stage, where there are no symptoms but bacteria remain in the body for years if untreated. In some cases, infection can later progress to tertiary syphilis, which may occur months, years, or even decades later and can affect the heart, brain, nerves, eyes, ears, and other organs. Neurological or eye involvement can occur at any stage, not only in late disease.
Syphilis diagnosis and treatment
Diagnosis relies on clinical assessment combined with laboratory testing.
Most diagnoses are made using blood tests that detect antibodies produced by the immune system in response to infection. In Australia, syphilis screening is routinely performed in pregnancy, typically in the first trimester, using these serological tests. The diagnosis can also be made using PCR testing on a swab from a syphilitic ulcer.
If there is concern that the infection has affected the nervous system, further testing may be required, including examination of cerebrospinal fluid obtained through a spinal tap procedure.
Treatment depends on the stage of infection and usually involves injections of penicillin. Follow-up blood testing after treatment is important to confirm response and ensure the infection has cleared.
Syphilis prevention
There is currently no vaccine available for syphilis, so prevention is based entirely on reducing exposure during sexual contact. Correct and consistent use of condoms with water-based lubricant for vaginal, anal, and oral sex reduces the risk of transmission, although it does not eliminate it completely. Dental dams may also be used during oral sex as an additional protective measure.
Sexual contact should be avoided if either partner has visible ulcers or sores on the genitals or mouth, as these lesions are highly infectious and can transmit syphilis at any stage of disease.
Regular sexual health screening is an important part of prevention, particularly after new or casual sexual partners, including while travelling overseas. Early infection can be completely asymptomatic, so testing is more reliable than relying on symptoms alone. Travellers planning extended time overseas or anticipating new sexual partners should consider a sexual health check as part of their pre-travel consultation.