Syphilis: The Return Of The ‘Great Pox’

Syphilis is one of the most infamous Sexually Transmitted Infections (STIs), yet is now often associated and consigned to history- a disease that used to cut great ravages through Europe, but in the modern age is more often than not just a footnote at the bottom of an article. However, this is changing with syphilis infecting around 12 million new people annually and in the UK alone cases of syphilis have increased by 33% in just a year (1). So what is syphilis, and why is it still a threat to modern health?

Syphilis is an STI that is caused by the bacterium, Treponema pallidum, and its distinctive spiral shape is clearly seen under a microscope. It is transmitted through blood, including from mother to foetus, and has 3 distinct stages as a disease. The primary stage occurs soon after the initial infection, symptoms at this stage include rash and most distinctly chancre. Chancres are painless ulcers or sores found on the skin. These symptoms clear up on their own after several weeks. Secondary syphilis occurs 1-2 months after the initial infection. The symptoms change to rashes and inflamed nodules. Finally tertiary syphilis can occur 3-30 years after the initial infection. The symptoms for tertiary syphilis are far more severe than the previous two stages. Open lesions on the skin, called Gumma appear, lesions may also be internal, found in the brain, cardiovascular system and bone. It causes swellings and these, combined with the Gumma, often give the appearance to a person that their face is rotting away. Syphilis can also cause dementia, meningitis and degeneration of spinal cord nerves. Untreated, syphilis has a mortality rate of between 8% and 58%- odds that you wouldn’t want to bet on. Congenital syphilis, i.e. syphilis spread from mother to foetus, causes miscarriages or death of the baby shortly after birth in 40% of cases.

It would be expected that a disease with traits as distinctive as syphilis would be easy and quick to identify, however many carriers of syphilis are unaware that they are so. This is usually due to both primary and secondary syphilis symptoms resolving themselves, therefore people believe that is was just a temporary infection and never seek medical help. Often carriers don’t realise they have syphilis until the tertiary symptoms emerge up to 30 years later, this allows them to potentially infect many more people.

In the past, syphilis used to be far more virulent and widespread. It first emerged in Europe in the late 1400s and is thought to have been brought back to Europe from the Americas by Columbus. Back then the strain was far more deadly, causing the flesh to rot away and pustules to form, killing in a few months. The current strains of syphilis are far less deadly, due to both better treatment (previously, the toxic element mercury was often used) and the theory that the actual bacterium has lost some of virulence.

Diagnosing syphilis accurately requires a blood test, often using direct fluorescent antibody testing, where specific antibodies that are tagged with fluorescein bind to syphilis proteins. Syphilis is often called the ‘Great Pretender’, this is because symptoms are often rapidly changing and take on the appearance of other diseases which can lead to misdiagnoses. To add to the confusion, it is extremely hard to study syphilis as T. palladium cannot be grown in a medium culture and is only able to develop in a mammal host.

The antibiotics of choice used to treat syphilis are penicillin G, doxycycline and tetracycline. Syphilis used to also be treatable with various other antibiotics, but most syphilis strains evolved resistance to these. Once syphilis reaches the tertiary stage it becomes harder to treat, with Penicillin struggling to penetrate to the central nervous system. By this stage there will also be irreversible damage caused by the bacteria.

At the time of the 21st century syphilis appeared to be slowly, but surely dying out. With effective treatments and better education in safe sex practices, syphilis was mostly just considered a problem in less economically developed countries. However, recently syphilis is going through a revival, cases are rapidly increasing in many ‘developed’ countries, including the UK, USA, Canada and many European countries (4).Cases in the UK increased by 33% in a year, while the USA had increases of 11% and, in certain heavily populated areas, the increase was far greater with Central New York showing an increase in cases of 111% (5). In the USA congenital syphilis is a particular concern, with cases of it in California increasing by over 230% in one year (6). In particular, cases of syphilis are increasing fastest among homosexual males, in the USA 75% of all new cases were in this group, while in the UK, syphilis cases among this social category increased by 46%.

This re-emergence of syphilis is blamed on many different reasons. Firstly, as aforementioned, syphilis is hard to diagnose, with constantly changing symptoms that vanish and then re-emerge and the modern strain of syphilis is also, in its early stages, often asymptomatic in woman (50-80% show no symptoms). And primarily it is this lack of symptoms that allows syphilis to spread undetected through a population. Syphilis tests are also generally more expensive to perform than other STI tests, this is due to its abilities to imitate other diseases, allowing it to hide in plain sight and therefore a blood test must be used to diagnose it. Often the VDRL test is also used to check for a syphilis antibody presence in a patient, however the antibody it detects is not specific for syphilis and therefore if the result is positive a more expensive and specific second blood test must occur.

Some medical experts are blaming the rise of syphilis on the increased prevalence of casual sex, with apps like Tinder and Grindr allowing quick hook-ups where the participants may not use protection, allowing the unchecked increase of syphilis (7). Regardless, all of these increases around the globe suggest that syphilis is not a problem to be consigned to the past with the disease still being very much a part of modern life. Though the modern strain of syphilis is not as fatal and virulent as in the past, it can still be fatal or at least produce debilitating effects. With the rise of antibiotic resistance, treating syphilis is only getting harder and while penicillin is still mostly effective, syphilis has evolved resistance to many antibiotics already. These large increases of syphilis cases must be slowed down before wide-spread antibiotic resistance, otherwise a large number of people will be at risk from the disease. Ultimately, the best way to combat the rise of syphilis is simply to practice safe sex practices, such as wearing a condom and getting frequent STI checks.

By Katie Harper


(1) Gov UK. 2013. Infectious syphilis and congenital syphilis: recent epidemiology. [Online]. [7th November 2015]. Available from:

(2) viPathogen Profile Dictionary. 2010 Treponema pallidum. [Online]. [7th November 2015]. Image available from:

(3)  Wikipedia. 2015 Syphilis. [Online]. [7th November 2015]. Image available from:

(4)  Eurosurveillance. 2012. Rapid increase in gonorrhoea and syphilis diagnoses in England in 2011. [Online]. [7th November 2015]. Available from:

(5) CNYCentral. 2015. Syphilis cases in Central New York increase 111% in one year. [Online]. [7th November 2015]. Available from:

(6)Cobas. 2015. Syphilis: The return of a historic disease. [Online]. [7th November 2015]. Available from:

(7) The Independent. 2015. Tinder and Grindr dating apps blamed for surge in cases of HIV, syphilis and other STDs. [Online]. [7th November 2015]. Available from:

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