Screening for Chlamydial Infection: A Summary of the Evidence

In the United States, Chlamydia trachomatis is the most common sexually transmitted bacterial pathogen. There are estimated to be 3 million new infections each year. Chlamydial genital tract infections are a major cause of urethritis, cervicitis, and pelvic inflammatory disease (PID) in women and are an important cause of ectopic pregnancy, infertility, and chronic pelvic pain. Chlamydial infections are responsible for 25% to 50% of the 2.5 million cases of PID that are reported annually in the United States. Infections are also related to adverse pregnancy outcomes such as miscarriage, premature rupture of membranes, preterm labor, low birth weight infants, infant mortality, and postpartum infections. Perinatal transmission to infants can cause neonatal conjunctivitis and pneumonia. Chlamydial infection in men is the cause of 30% to 40% of the 4 to 6 million visits each year for nongonococcal urethritis and 50% of more than 150,000 cases of acute epididymitis. Rarely, men may experience chronic complications of chronic prostatitis, reactive anthritis, urethral strictures and possibly infertility. Chlamydia is a cofactor in transmission of human immunodeficiency virus infection. In the United States in 1994, the estimated cost of untreated chlamydial infections and their complications was $2 billion.