Ten teenagers have been diagnosed with syphilis in central Oklahoma over the last four weeks, prompting health officials to warn young people of the dangers of this sexually transmitted disease and the risk of having unprotected sex.

A total of 15 people age 18 or younger were confirmed with the disease all of last year in Oklahoma, so 10 cases in a month's time is alarming, health officials said Wednesday.

Some of the cases appear to be arising from parties where young people have unprotected group sex, said Jan Fox, who heads the Oklahoma Department of Health's sexually transmitted disease service.

"We've gotten that information from interviewing some of the cases involved and also from county health departments," she said. "We believe there is a growing popularity of teens attending these parties, and that may be fostering the spread of syphilis."

The bacterial disease can lead to major health problems and birth defects if untreated.

Fox said young people should seek testing and treatment if they have been having unprotected sex, particularly with multiple partners. Free testing and treatment is available at local county health departments.

More than 4,000 new sexually transmitted infections occur each year in Oklahoma among people 18 and younger. In all of 2008, 249 cases of syphilis were reported in Oklahoma, but all but 15 involved older people.

Fox said she couldn't specify what central Oklahoma counties were involved in the recent outbreak because of concerns over confidentiality.

"They are multiple counties in the central part of the state and we're very concerned it could spread beyond that," she said. "Teenagers across the state could be at risk.

"It's very alarming because syphilis is a disease that can be very harmful. It can lead to very adverse health events if left untreated. It can eventually through time impact major organs of the body including the brain and the heart."

Syphilis is a curable infection.

"The good news is that syphilis can be identified by examination and testing, cured with antibiotics, and through disease investigation, the spread of syphilis can be stopped," State Epidemiologist Dr. Kristy Bradley said.

In its early stages, the disease creates a lesion or sore, that can go away but still leave the carrier capable of infecting others.

"There are many effective ways to prevent, diagnose, and treat syphilis and other STDs," Fox said. "Consistent condom use is one effective way to prevent becoming infected with STDs including syphilis.

"Once infected, STD screening and early diagnosis are vital to prevent serious health consequences and increased transmission. Screening is particularly important since many STDs often have no signs or symptoms."