Untreated, syphilis can stay in your body for life and can lead to disfigurement, brain damage and end in death.

What are the signs?

Most of the time there will be no symptoms. Initially though, between three weeks to 90 days after infection, you'll notice sores or open, wet ulcers on your bits, mouth or anus. These may come and go for anything up to two years! You may get rashes on your hands and feet, headaches, sore throat, swollen glands, tiredness, weight and hair loss and muscle pains. One third of people who don't get it treated experience damage to the heart, brain, nerves or other organs.

The disease is mostly contagious in the early stages. The discharge from the sores is highly infectious. Although it becomes less so in the later stages, untreated it can be spread from a pregnant woman to her unborn baby, causing serious birth defects.

How's it caught?

The scary thing is that it isn't just through straight, anal or oral sex that it can be transmitted, but through kissing too. So, make sure you know who you're snogging! You have an increased chance of getting it if you are sexually active or if your partner's sexually active, if you don't use a condom or if you keep catching STIs.

So how are you gonna protect yourself?

Most importantly, don't have sex until you've finished treatment. Make sure you tell any partners if you're infected, have your partner tested and treated at the same time and use a condom every time (that goes for lasses as well as lads!)