People using social networking sites for casual sex are to blame for a four-fold increase in syphilis, a director of public health said today.
Professor Peter Kelly, who works for NHS Tees, said the biggest cause of spreading the serious disease was unprotected sex.
He said syphilis has risen sharply among heterosexuals in his area in the last year, and is potentially dangerous for pregnant women as it could lead to miscarriage, still-birth or disability.
Symptoms depend on the development of the disease, and at first many sufferers are unaware of any problem.
Prof Kelly warned people using the internet to find sex to protect themselves.
The public health expert said: "There has been a four-fold increase in the number of syphilis cases detected, with more young women being affected.
"Syphilis is a devastating disease which can lead to serious health problems to the infected individual, their sexual contacts and an unborn child (in pregnant women).
"It is easily preventable and treatment is simple and effective.
"Unprotected sex, especially with casual partners, is the biggest risk for syphilis.
"Social networking sites are making it easier for people to meet up for casual sex.
"It is important that people avoid high-risk sexual behaviours and practise safe sex to protect themselves from sexually-transmitted infections.
Nationally, the highest rates of syphilis are seen in women aged 20 to 24 and men aged 25 to 34.
In 2008 there were 3,588 cases diagnosed in sexual health clinics across the UK.
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