Last week, at a national conference on sexually transmitted diseases (STDs), the Centers for Disease Control and Prevention (CDC) released the results of a study indicating that at least one in four teenage girls nationwide had a sexually transmitted disease. Among the teenage girls tested, the study found that 18 percent were infected with human papilloma virus (HPV) - the virus that causes cervical cancer and genital warts - 4 percent were infected with chlamydia, 2.5 percent had trichomoniasis, and 2 percent were infected with herpes simplex virus.

Sexually transmitted diseases are a major problem among adolescents because the adolescent often is not aware that he or she is infected, and unprotected sex allows them to unknowingly spread of infection to others. The Philadelphia Department of Public Health has been aware of the problem of STDs among our teenagers for many years and is taking positive steps to address this epidemic.

The extent of the problem in Philadelphia is significant. In 2003, the CDC's Youth Risk Behavior Survey determined that 64 percent of Philadelphia high school students were sexually active. Last year, 1,790 boys and 5,198 girls 15 to 19 years old were reported with chlamydia, and an additional 505 boys and 1,003 girls were infected with gonorrhea. This means that about one out of every 10 girls in this age group was found to be infected with chlamydia or gonorrhea.

Teens accounted for more than 36 percent of the total number of cases of chlamydia and gonorrhea reported citywide last year. Because HPV, trichomonas and genital herpes, the other STDs included in the CDC study, are not reportable to the Department of Public Health, we do not know precisely how many adolescents in Philadelphia have been infected. However, based on data from the city's public clinics and information provided by private health-care providers, the number of teenagers with these STDs is likely to be substantial.

To address the STD problem among adolescents, the Philadelphia health department has implemented what we believe is the most aggressive testing and treatment program for chlamydia and gonorrhea among teenagers in any major city nationwide. In addition to supporting STD testing of teens in family planning clinics and the city's health care centers, free, confidential STD testing has been offered in a variety of novel settings, such as at recreation centers, Family Court, and the Youth Study Center.

In 2002, we initiated a pilot STD screening/education program in two high schools that was so successful, it was expanded the following year to include all public high schools, with the full cooperation and support of the Philadelphia School District. This program, which tests between 16,000 and 20,000 students annually, has been emulated in many other major metropolitan areas. In total, the Philadelphia Department of Public Health has increased annual STD screening from 88,000 tests in 2000 to more than 160,000 tests in 2007, with the majority of this increase accounted for by testing of teens.

But clearly more needs to be done. Adolescents need to understand better the risks associated with unprotected sex. If not yet sexually active, adolescents should be encouraged to delay the initiation of sex until they are older. If sexually active, they should be encouraged to use latex condoms consistently and correctly.

Teenage girls and young women should be vaccinated against HPV to protect them from cervical cancer later in life. Efforts should be made to administer the vaccine to girls before potential exposure to HPV through sexual contact. And adolescents should be told that if they become infected with an STD, they should seek treatment immediately and advise all of their sex partners to seek treatment, too. In Philadelphia, adolescents can be examined and treated for an STD without parental consent or notification. Adolescents need to know this so that they do not delay seeking medical help.

Whose job is it to educate, motivate and assist teenagers in a way that will help them avoid STDs and their complications? I propose that it is all of our jobs: parents, grandparents, aunts, uncles, teachers, coaches, counselors, clergy, physicians, nurses, pharmacists, health department staffs, peers, and other responsible adults who are involved in the lives of our adolescents.

All who have an opportunity to educate adolescents about STDs should seek correct and up-to-date information and then play a role in this effort. Adults must model responsible sexual behavior if teens are to believe that we mean what we say. The Department of Public Health will continue to provide information, testing, vaccination, and prevention opportunities for teenagers, but if we are to succeed in lowering STD rates among adolescents in Philadelphia, all of us must make this a priority.