disease

The latest data on the prevalence of chlamydia, gonorrhea and syphilis reveal a growing public health problem, with its severest effects on women, young people and members of minorities.

All three diseases are preventable, treatable with antibiotics, and, at least in their early stages, completely curable. Yet they persist, partly because people can spread them without knowing they are infected.

All three diseases are transmitted through vaginal, oral and anal sex. Untreated chlamydia or gonorrhea in women can lead to painful and long-lasting pelvic inflammatory disease, infertility and potentially fatal ectopic pregnancy; both can be transmitted to babies at birth. Syphilis has various severe symptoms depending on the stage of the disease, can be passed by pregnant women to their babies, and can persist for a lifetime in both men and women.

''Condoms are a very good way to reduce the risk of getting infections,'' said Dr. Stuart Berman, an epidemiologist with the Centers for Disease Control and Prevention, which issued the report. ''If you use them all the time, and use them correctly, they work.''

Screening is also helpful. ''Pregnant women and men who have sex with men should be screened yearly for chlamydia, gonorrhea and syphilis,'' Dr. Berman said. ''And all sexually active women younger than 26 should be screened annually for chlamydia.'' (Women's rates of chlamydia are almost three times those of men.)

These numbers, which were published in December, include only cases reported by local health departments, clinics and hospitals. The C.D.C. estimates that they account for less than half of the actual number of infections. NICHOLAS BAKALAR