Syphilis on the Rise

Once considered rare and nearly eliminated, syphilis is now making a global comeback—and Aotearoa New Zealand is no exception. Infections have surged to record highs, affecting more women and leading to preventable congenital cases. Despite being easy to diagnose and treat, syphilis often goes unnoticed, making regular testing and awareness critical to stop its spread.

Isn’t syphilis a rare type of sexually transmitted infection (STI)?

Yes, up until the early 2000s syphilis was a far less common STI and was even thought to be at the point of elimination.¹ Syphilis is known as “the great imitator” because its symptoms can mimic other infections. Many people don’t have any symptoms and if they do, the symptoms resolve and it seems like the infection has gone. Syphilis can be transmitted without visible symptoms.

Global resurgence of syphilis

There is a noticeable trend of increasing numbers of syphilis infection in multiple countries worldwide.² Syphilis is now common and increasing in New Zealand, with infections nearly doubling in the general population between 2022 and 2023, reaching the highest numbers of infection on record.³ Historically syphilis has been most common in gay and bisexual men but the rates of women becoming infected are rising. Maori and Pacific Islanders have significantly higher rates of infection than other ethnic groups.

What has caused this resurgence?

The resurgence is thought to be due to a number of factors:

• A change in sexual practices – a higher incidence of unprotected casual sex.
• Decreased condom use – due to a decrease in the perceived risk of HIV infection.
• Dating apps- an increase in anonymous sexual partners make partner contact identification and tracing more difficult.
• Covid pandemic– routine STI testing and public health service disruptions were a result of the pandemic. During this time there was also decreased funding for STI prevention programmes along with STI clinic closures and redirection of health staff.

What causes syphilis and how is it treated?

Syphilis is caused by the bacterium, Treponema pallidum. It is very infectious and easy to catch via very close skin-to-skin or genital contact. It is also transmitted in pregnancy and through blood transfusions. Generally, it is a very easy disease to diagnose and treat, and the treatment is usually widely available. The primary treatment is a short course of penicillin, delivered by intra-muscular injection. There are alternative antibiotics available for people with a penicillin allergy. The duration of treatment depends on the stage of the infection, ranging from one day to three weeks. One dose of penicillin injection will cure early syphilis infection.⁴

What happens if syphilis is left untreated?

Syphilis has very serious consequences if left untreated. In the late stage of the disease (10 to 30 years after the initial infection) there can be damage to the brain, heart and other organs such as the liver, bones and joints. The disease causes cardiovascular damage such as heart failure, aortic aneurysms and heart valve disease. It causes neurological symptoms such as brain damage, dementia, blindness, deafness, and nerve problems like numbness and coordination difficulties.

Congenital syphilis is where the mother passes the infection to their child during pregnancy, potentially causing stillbirth, infant death, low birth weight and premature birth along with life-long health problems including blindness, deafness, developmental delays and seizures.

Syphilis has four stages of infection

• Primary infection – Symptoms can take up to 90 days to appear. A round, painless sore develops in the genital area (also called a chancre). Sometimes this is not noticed if it is inside the body but infection is still present. If this stage is left untreated the disease progresses to secondary infection.
• Secondary infection – a non-itchy skin rash often appears on the palms and soles of the feet. Swollen lymph glands, headaches, tiredness, muscle and joint aches, hair loss, warty growths in skin folds and fever are other common symptoms of this stage.
• Latent non-infectious stage – At this stage the bacteria are still present in the body but there are no symptoms and the person is not infectious. However, the infection can be causing damage to the body.
• Tertiary stage – In this late stage of infection the organs of the body are affected. The person is not contagious but may be experiencing symptoms such as numbness, vision problems, dementia and difficulty controlling muscle movements.⁵

Get a full STI check

This means not just a urine test and swab but also a blood test to check for HIV and syphilis. You can catch syphilis more than once so it is important to understand that treatment of syphilis will not protect against future infections. Using a condom will decrease the chance of being infected but they do not provide 100% protection. Regular blood tests are an important way to stay well and detect the disease before any long-term damage can occur.