Sexual health

Everything old is new again: don’t forget about syphilis

Phillip Read



Notifications of infectious syphilis are continuing to rise. This article summarises key information on testing, treatment and follow up that is essential to primary care.

Article Extract

After a historical low in the 1990s, syphilis notifications have increased in Australia every year for the past 15 years. Despite a range of prevention methods and the availability of a cheap single-dose cure to which no antimicrobial resistance has developed, this infection shows no signs of slowing. Syphilis is an important disease in its own right with serious sequelae if untreated. Crucially, it is also a risk factor for HIV transmission and acquisition. 

Treponema pallidum subsp. pallidum, the causative organism, is a member of the Spirochaetaceae family of bacteria. Humans are the only host, and transmission is almost entirely attributable to sexual contact and, outside of Australia, vertical transmission. Structurally, T. pallidum is spiral shaped, 0.2 μm in diameter and varies from 6 to 15 μm in length. Endoflagellae facilitate the characteristic corkscrewing movement seen under the microscope. 

Picture credit: © Chris Bjornberg/