Lesson 5: Public Health Surveillance

Appendix B. CDC Fact Sheet on Chlamydia

What is chlamydia? Chlamydia is a common sexually transmitted disease (STD) caused by the bacterium, Chlamydia trachomatis, which can damage a woman's reproductive organs. Even though symptoms of chlamydia are usually mild or absent, serious complications that can cause irreversible damage, including infertility, can occur without notice before a woman ever recognizes a problem. Chlamydia also can cause discharge from the penis of an infected man.

How common is chlamydia? Chlamydia is the most frequently reported bacterial STD in the UnitedStates. In 2002, a total of 834,555 chlamydial infections were reported to CDC from 50 states and the District of Columbia. Underreporting is substantial because the majority of persons with chlamydia are not aware of their infections and do not seek testing. Also, testing is not often performed if patients are treated for their symptoms. An estimated 2.8 million Americans are infected with chlamydia each year. Women are frequently re-infected if their sex partners are not treated.

How do people contract chlamydia? Chlamydia can be transmitted during vaginal, anal, or oral sex. Chlamydia can also be passed from an infected mother to her baby during vaginal childbirth. Any sexually active person can be infected with chlamydia. The greater the number of sex partners, the greater the risk for infection. Because the cervix (opening to the uterus) of teenage females and young women is not fully matured, they are at particularly high risk for infection if sexually active. Because chlamydia can be transmitted by oral or anal sex, men who have sex with men are also at risk for chlamydial infection.

What are the symptoms of chlamydia? Chlamydia is known as a "silent" disease because approximately three quarters of infected women and half of infected men have no symptoms. If symptoms do occur, they usually appear within 1–3 weeks after exposure.

Among women, the bacteria initially infect the cervix and the urethra (urine canal). Women who have symptoms might have an abnormal vaginal discharge or a burning sensation when urinating. When the infection spreads from the cervix to the fallopian tubes (the tubes that carry eggs from the ovaries to the uterus), certain women still have no signs or symptoms; others have lower abdominal pain, low back pain, nausea, fever, pain during intercourse, or bleeding between menstrual periods. Chlamydial infection of the cervix can spread to the rectum.

Men with signs or symptoms might have a discharge from their penis or a burning sensation when urinating. Men might also have burning and itching around the opening of the penis. Pain and swelling in the testicles are uncommon symptoms.

Men or women who have receptive anal intercourse might acquire chlamydial infection in the rectum, causing rectal pain, discharge, or bleeding. Chlamydia has also been identified in the throats of women and men having oral sex with an infected partner.

What complications can result from untreated chlamydia? If untreated, chlamydial infections can progress to serious reproductive and other health problems with both short- and long-term consequences. Similar to the disease itself, the damage that chlamydia causes is often asymptomatic.

Among women, untreated infection can spread into the uterus or fallopian tubes and cause pelvic inflammatory disease (PID). This happens among ≤40% of women with untreated chlamydia. PID can cause permanent damage to the fallopian tubes, uterus, and surrounding tissues. The damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy (pregnancy outside the uterus). Women infected with chlamydia are ≤5 times more likely to become infected with HIV, if exposed.

To help prevent the serious consequences of chlamydia, screening at least annually for chlamydia is recommended for all sexually active women aged ≤25 years. An annual screening test also is recommended for women aged ≥25 years who have risk factors for chlamydia (a new sex partner or multiple sex partners). All pregnant women should have a screening test for chlamydia.

Complications among men are rare. Infection sometimes spreads to the epididymis (a tube that carries sperm from the testis), causing pain, fever, and, rarely, sterility. Rarely, genital chlamydial infection can cause arthritis that can be accompanied by skin lesions and inflammation of the eye and urethra (Reiter syndrome).

How does chlamydia affect a pregnant woman and her baby? Among pregnant women, evidence exists that untreated chlamydial infections can lead to premature delivery. Babies who are born to infected mothers can contract chlamydial infections in their eyes and respiratory tracts. Chlamydia is a leading cause of early infant pneumonia and conjunctivitis (pink eye) among newborns.

How is chlamydia diagnosed? Laboratory tests are used to diagnose chlamydia. Diagnostic tests can be performed on urine; other tests require that a specimen be collected from such sites as the penis or cervix.

What is the treatment for chlamydia? Chlamydia can be easily treated and cured with antibiotics. A single dose of azithromycin or a week of doxycycline (twice daily) are the most commonly used treatments. HIV-positive persons with chlamydia should receive the same treatment as those who are HIV-negative.

All sex partners should be evaluated, tested, and treated. Persons with chlamydia should abstain from sexual intercourse until they and their sex partners have completed treatment; otherwise re-infection is possible.

Women whose sex partners have not been appropriately treated are at high risk for re-infection. Having multiple infections increases a woman's risk for serious reproductive health complications, including infertility. Retesting should be considered for females, especially adolescents, 3–4 months after treatment. This is especially true if a woman does not know if her sex partner has received treatment.

How can chlamydia be prevented? The surest way to avoid transmission of STDs is to abstain from sexual contact or to be in a long-term mutually monogamous relationship with a partner who has been tested and is known to be uninfected. Latex male condoms, when used consistently and correctly, can reduce the risk of transmission of chlamydia.

Chlamydia screening is recommended annually for all sexually active women aged ≤25 years. An annual screening test also is recommended for older women with risk factors for chlamydia (a new sex partner or multiple sex partners). All pregnant women should have a screening test for chlamydia.

Any genital symptoms (e.g., discharge or burning during urination or unusual sores or rashes) should be a signal to stop having sex and to consult a health-care provider immediately. If a person has been treated for chlamydia (or any other STD), he or she should notify all recent sex partners so they can see a health-care provider and be treated. This will reduce the risk that the sex partners will experience serious complications from chlamydia and will also reduce the person's risk for becoming re-infected. The person and all of his or her sex partners should avoid sex until they have completed their treatment for chlamydia.

Adapted from: Chlamydia — CDC Fact Sheet [Internet]. Atlanta: CDC [updated 2006 April; cited 2006 May 17]. Available from: http://www.cdc.gov/std/chlamydia/STDFact-Chlamydia.htm.