With figures on the rise how can syphilis affect you?
Doctors say there's been a rise in the number of teenagers getting syphilis.
They say in the past it's mainly been older people and gay men who they've treated for the sexually transmitted infections (STI).
Health experts say in the last five years several groups of teenagers have tested positive.
They say more people having sex after meeting online makes it harder to trace those infected.
The rate of new cases of the STI is at its highest in 50 years.
What is syphilis?
Syphilis is a bacterial infection that is usually passed on through having sex with someone who is already infected.
It can also be passed from an infected mother to her unborn child and, in rare cases, can be caught through injecting drugs.
The first written records of an outbreak of syphilis occurred in the late 1400s in Naples, Italy, during a French invasion.
The STI can form in one of three different stages, according to the NHS.
Stage one: Primary syphilis
Symptoms of syphilis begin with a painless but highly infectious sore on the genitals or sometimes around the mouth.
Most people only have one but some may experience more.
These open sores can lead to a higher risk of getting HIV because infected fluids can more easily enter the bloodstream.
The sore usually lasts two to six weeks before disappearing.
If the condition is not treated, syphilis will move into its second stage.
Stage two: Secondary syphilis
Skin rashes and a sore throat can develop a few weeks after the disappearance of the sore.
These symptoms may disappear within a few weeks, after which a hidden phase may occur and can last for years.
After a couple of years, you cannot pass the infection to others, even though you remain infected.
Without treatment, there is a risk that syphilis will move on to its most dangerous stage.
Third stage: Tertiary syphilis
At this stage it can cause serious damage to the body, possibly even death.
The symptoms of tertiary syphilis can begin years or even decades after the initial infection.
The nature of tertiary syphilis will depend on what part of the body the infection spreads to.
Things like loss of coordination, paralysis and blindness are all possible symptoms.
Despite rumours, syphilis cannot be contracted through toilet seats, sharing eating utensils or clothing.