Resurgence of syphilis in high-income countries means retraining of doctors is necessary

The resurgence of syphilis in high income countries, after low incidence for the past two decades, has left many doctors unfamiliar with the many manifestations of the disease. This recent resurgence demands renewed vigilance among, and training of, doctors and health-care professionals. These are the conclusions of authors of a Review in the April edition of The Lancet Infectious Diseases.

Dr Kevin Fenton, Centers for Disease Control and Prevention, Atlanta, GA, USA, and colleagues say: "In many high-income countries, successes in syphilis prevention and control were accelerated during the early and mid-1990s, with many countries approaching or achieving elimination of endemic disease transmission. However, since the beginning of the 21st century, syphilis incidence has started to rise in high-income settings, in part driven by increases in cases among men who have sex with men, although more recent increases among heterosexual people have also been reported."

Syphilis, which infects some 12 million people worldwide every year, is caused by the bacteria Treponema pallidum . These particular "treponemes" are parasites that can only live in human hosts and are not found in other animals or the environment. Most cases of syphilis are acquired through direct sexual contact with lesions of an individual who has active primary or secondary syphilis -- transmission occurs in around half of such contacts. It can also transmitted by women to their unborn fetus. Around 2–6 weeks post-infection, a primary lesion develops which turns into a hard-based, ulcerated lesion. Secondary syphilis is caused by multiplication of treponemes throughout the body, which can lead to fever, headache, rash on the palms and feet, and a range of other symptoms, including secondary lesions -- these lesions usually subside within a few weeks. Syphilis can then remain latent in those infected for many years -- in some cases for the rest of the patient's life. Tertiary syphilis -- when treponemes invade many systems of the body, leading to various complications or even death -- is rare nowadays thanks to antibiotic treatment. The unique complications associated with syphilis in patients with HIV infection are also discussed in detail.

Whilst acknowledging that syphilis is particularly problematic in developing countries, the Review focuses on the alarming recent trends in high-income countries. The authors say: "Since 1996, syphilis has been on the increase in many northern and western European Union countries." For example, Belgium reported a 3•5 fold increase in syphilis cases between 2000 and 2002, while cases in Austria steadily increased from a low point of 124 in 1993 to 420 in 2002. The authors say: "Other major urban centres such as London, Dublin, Berlin, Paris, and Rotterdam all showed huge increases in syphilis reports during this period, predominantly among populations of men who have sex with men. Increases in the UK were initially observed in larger cities, then progressed to suburban and rural settings." Increases have also been reported in Canada, Australia, and New Zealand.

In the USA, the demographics of the disease have changed dramatically over the past 30 years, shifting from predominantly men who have sex with men at the beginning of the HIV/AIDS epidemic, to socio-economically disadvantaged heterosexual African Americans, especially in the rural areas in the early 1990s, associated with a concomitant crack-cocaine epidemic, and more recently to within men who have sex with men. This most recent resurgence since 2000 has continued unabated. The recent increases in men who have sex with men have in part been driven by contemporary social interactions -- use of Viagra and amphetamines, saunas, circuit parties, and the internet -- all of which influence sexual mixing patterns and increase transmission risk.

Benzylpenicillin is used to treat syphilis in all its stages, with mode of administration dependent on the area of the world the patient is in. Various public-health strategies can help control the disease, such as screening high-risk populations and new rapid diagnostic tests (eg, saliva) to identify and treat infected people. The authors say: "Other proven interventions, such as mass-media campaigns, interventions to change high-risk behaviour in groups with a high prevalence of syphilis infection, distribution and use of condoms, expanded screening especially in outreach settings, and linkage to care, are all useful tools to prevent syphilis in community settings."

They conclude: "In developed countries, the low incidence of syphilis over the past two decades and the interactions of the disease with HIV infection have resulted in clinicians who are unfamiliar with the disease's many manifestations. The recent resurgence among men who have sex with men and some high-risk heterosexual couples raises cause for concern, and demands renewed vigilance among, and training of, health-care professionals. Similarly, efforts must be made to incorporate and evaluate new diagnostic social tools, social network approaches, innovative evidence-based prevention interventions, robust disease surveillance, and systematic monitoring and evaluation of prevention, treatment, and care activities."