Syphilis - an STI on the rise, again

April is STD Awareness Month and we believe it is time to focus on this important topic. According to the WHO (World Health Organization) around 1 million STIs are acquired every day worldwide.

In the previous weeks, we talked about STIs, STDs and VDs and the differences between them and about some of the most common STIs, Chlamydia and Gonorrhea.

Now we are sharing some very interesting facts about another common STI, that unfortunately is making its way back, the one and only Syphilis.

What is Syphilis and what are the symptoms? Let’s find out!

Syphilis is a sexually transmitted disease acquired through an infection with the bacterium Treponema pallidum, and it affects only humans. It was first discovered in the 15th century in Europe and was a mystery to many. Only four centuries later was it medically identified. Throughout history, many public figures, such as politicians, musicians and literature writers got infected with this bacteria. Thankfully, with the discovery of penicillin and effective public measures, syphilis had a decline in the United States and Europe.

Syphilis still remains a public health concern as in the last decades, in Western Europe, the USA and China cases of syphilis have shown an increase in MSM (men who have sex with men), while in low and middle-income countries syphilis has remained an endemic (commonly spread disease that is present in specific regions). In 2018, men accounted for almost 90% of syphilis cases. More than half of them reported having sex with men and approx. 40% of them were infected with HIV (Human Immunodeficiency Virus), as syphilis increases the risk of infection with HIV through the open wounds that develop. Besides HIV, syphilis can be accompanied by other STIs as well.

Each year, around 11 million new cases of syphilis develop in people aged 15 to 49 years worldwide. With a high transmission rate, up to 30% of individuals that have sexual contact with an infected person acquire the infection as well. The spread of syphilis can be controlled but it is dependent on the early diagnosis and treatment.


  • Skin to skin contact during sexual activity (vaginal, anal and oral sex)

  • From mothers to babies, during the pregnancy in the uterus or during birth

  • Through blood transfusions (rare)

  • Organ donors (rare)

  • Occupational exposure (via accidental injury, transmission through blood)

  • Through human bite in both sexual and non-sexual circumstances

  • Through mouth-to-mouth feeding of infants with pre-chewed food from infected relatives

Risk categories where diagnosis and screening is difficult due to stigma and social constructs

  • MSM (men who have sex with men); MSM are reported to have a riskier sexual life.

  • People that have multiple sex partners

  • Sex workers

  • Transgender women