Chlamydia Information

Chlamydial ("kla-mid-ee-uhl") infection -- known as chlamydia -- is the most common bacterial sexually transmitted disease (STD) in the United States today. The U.S. Centers for Disease Control and Prevention estimates that more than 4 million new cases occur each year. The highest rates of chlamydia are in 15- to 19-year-old adolescents regardless of demographics or location. Pelvic inflammatory disease (PID), a serious complication of chlamydia, has emerged as a major cause of infertility among women of childbearing age. Chlamydia is caused by a bacterium, Chlamydia trachomatis, and can be transmitted during vaginal, oral, or anal sexual contact with an infected partner. A pregnant woman may pass the infection to her newborn during delivery, with subsequent neonatal eye infection or pneumonia. The annual cost of chlamydia is estimated to exceed $2 billion.

Chlamydia Symptoms

Most cases of chlamydia are silent, causing no symptoms. However, men and women with chlamydia may experience abnormal genital discharge or pain during urination. These early symptoms of chlamydia may be mild. If symptoms occur, they usually appear within one to three weeks after exposure. Two of every three infected women and one or two of every four infected men have no symptoms whatsoever. As a result, often the disease may not be diagnosed and treated until complications develop.

Doctors estimate that, in women, one-third of chlamydia cases result in PID. Often these infections are not diagnosed until PID or other complications develop. In men, rarely, chlamydia may lead to pain or swelling in the scrotal area, which is a sign of epididymitis, an inflammation of a part of the male reproductive system located near the testicles. Left untreated, this condition, like PID in women, can cause infertility.

Chlamydia can also cause proctitis (inflamed rectum) and conjunctivitis (inflammation of the lining of the eye). The bacteria also have been found in the throat as a result of oral sexual contact with an infected partner. In tropical climates, a particular strain of C. trachomatis causes an STD called lymphogranuloma venereum (LGV), which is characterized by prominent swelling and inflammation of the lymph nodes in the groin. Complications may follow if LGV is not treated; this infection is very rare in the United States.

Chlamydia Diagnosis

Chlamydia can be confused with gonorrhea because the symptoms of both diseases are similar; in some populations they occur together. The most reliable way to diagnose chlamydia is for a clinician to send a sample of secretions from the patient's genital area to a laboratory that will look for the organism using one of a wide variety of quick and inexpensive laboratory tests. Although attempting to grow the organism in specialized tissue culture in the laboratory is one of the most definitive tests, it is expensive and technically difficult to do, and test results are not available for three or more days.

Scientists have developed several rapid tests for diagnosing chlamydia that use sophisticated techniques and a dye to detect bacterial proteins. Although these tests are slightly less accurate, they are less expensive, more rapid, and can be performed during a routine checkup. These tests use a process called DNA amplification to detect the genes of the organisms in genital secretions. Recently, the U.S. Food and Drug Administration approved this process for detection of chlamydia in urine. This is a major step in diagnosing chlamydia because it does not require an invasive sample; it can be used in settings where performing a pelvic examination is not convenient or not feasible, e.g., in college health units and at health fairs. Results from the urine test are available within 24 hours.