Chlamydia levels have jumped by 21% in Dublin over the last year, new figures have shown.

Chlamydia is the most common sexually transmitted infection (STI) in the developed world. Usually, it has no obvious symptoms, especially in women, however if left untreated, it can lead to serious complications such as infertility, ectopic pregnancies and orchitis (inflamed testicles).

According to the Dublin Well Woman Centre, in the first 10 months of this year, 227 chlamydia infections have been diagnosed in its three centres. This is more than the full year total for each of the last three years.

Last year, 187 infections were diagnosed, with 220 in 2010 and 219 in 2009.

As is the case nationally, two in three people diagnosed with the STI were in the 20-30 age group. This, the centre said, indicates that young adults are engaging in risky sexual behaviour or are not taking the proper precautions to protect themselves.

"Chlamydia is primarily a young person's infection so it is very concerning that it is on the rise considering the amount of public health resources that have gone into promoting a ‘safe sex' message in recent years," commented the centre's medical director, Dr Shirley McQuade.

She emphasised the fact tht while the morning after pill is available over the counter in pharmacies and will help prevent an unplanned pregnancy, ‘it won't stop the transmission of sexual diseases. Only a condom can do this'.

However, she warned that even condoms cannot protect against all STIs.

"It's worth remembering that someone with chlamydia has risked exposure to other STIs, like herpes and genital warts, which may not be so straightforward to treat."

If diagnosed early, chlamydia can be treated with antibiotics.

"It is important to be aware that many people can have the infection and have little or no symptoms, making it all the more important that they discuss their sexual health concerns with a family planning doctor or their GP. It is also important that testing is readily accessible," Dr McQuade added.

The centre is appealing to young adults to be particularly careful during the upcoming Christmas party season.