May 2001
Chlamydia
Disease Information
What is chlamydia?
Chlamydia is a common sexually transmitted disease (STD) caused by Chlamydia trachomatis, a bacterium, which can damage a woman's reproductive organs. Because symptoms of chlamydia are mild or absent, serious complications that cause irreversible damage, including infertility, can occur "silently" before a woman ever recognizes a problem.
How do people get chlamydia?
Chlamydia can be transmitted during vaginal, anal, or oral sex. Chlamydia can also be passed from an infected mother to her newborn during vaginal childbirth.
How common is chlamydia?
Chlamydia is the most frequently reported bacterial sexually transmitted infection in the United States. More than 650,000 cases were reported in 1999, and three of every four reported cases occurred in persons under age 25. Under-reporting is substantial because most people with chlamydia are not aware of their infections and do not seek testing. An estimated 3 million Americans are infected with chlamydia each year. Chlamydia is so common in young women that, by age 30, 50% of sexually active women have evidence that they have had chlamydia at some time during their lives.
What are the symptoms of chlamydia?
Chlamydia is known as a "silent" disease because three quarters of infected women and half of infected men have no symptoms. The infection is frequently not diagnosed or treated until complications develop.
In women, the bacteria initially attack the cervix (opening to the uterus) and the urethra (urine canal). The few women with symptoms might have an abnormal vaginal discharge or a burning sensation when urinating. When the infection spreads from the cervix to the fallopian tubes, some women still have no signs or symptoms; others have lower abdominal pain, low back pain, nausea, fever, pain during intercourse, and bleeding between menstrual periods. Whenever the infection spreads past the cervix into the upper reproductive system, permanent and irreversible damage can occur.
Men with signs or symptoms might have a discharge from the penis and a burning sensation when urinating. Men might also have burning and itching around the opening of the penis or pain and swelling in the testicles, or both.
How soon after exposure do symptoms appear?
If symptoms do occur, they usually appear within 1 to 3 weeks of exposure.
How is chlamydia diagnosed?
There are two kinds of laboratory tests to diagnose chlamydia. One involves collecting a specimen from an infected site (cervix or penis) to detect the bacterium directly. Another test that is becoming widely available can accurately detect chlamydia bacteria in a urine sample. A Pap test is not a test for chlamydia; it is a test for abnormal cervical cells.
Who is at risk for chlamydia?
Sexually active men and women can be exposed to chlamydia bacteria during sexual contact with an infected person. The more sex partners a person has, the greater the risk of chlamydia infection. Babies are at risk of acquiring a chlamydial infection from their infected mother.
Sexually active teenagers and young women are especially susceptible to chlamydia bacteria because of the characteristics of the cells that form the lining of the cervical canal.
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. All sex partners must also be treated.
What complications can result from untreated chlamydia?
If untreated, chlamydia infection can progress to serious reproductive and other health problems with both short-term and long-term consequences. Like the disease itself, the damage that chlamydia causes is often "silent."
Untreated chlamydia in men typically causes urethral infection. Infection sometimes spreads to the epididymis (a tube that carries sperm from the testis), causing pain, fever, and, potentially, infertility.
In women, the chlamydia bacteria often infect the cells of the cervix. If not treated, the infection can spread into the uterus or fallopian tubes (egg canals) and cause an infection called pelvic inflammatory disease (PID). This happens in up to 40% of women with untreated chlamydia. PID can cause permanent damage to the fallopian tubes, uterus, and tissues surrounding the ovaries. This damage can lead to chronic pelvic pain, infertility, and potentially fatal ectopic pregnancy (pregnancy outside the uterus).
In pregnant women, there is some evidence that chlamydia infections can lead to premature delivery. Babies who are born when their mothers are infected can get chlamydial infections in their eyes and respiratory tracts. Chlamydia is a leading cause of early infant pneumonia and conjunctivitis (pinkeye) in newborns.
Compared to women who do not have chlamydia, women infected with chlamydia may also have higher risk of acquiring HIV infection from an infected partner. Chlamydia can cause proctitis (an infection of the lining of the rectum) in persons having receptive anal intercourse. The bacterium also can be found in the throats of women and men having oral sex with an infected male partner.
How can chlamydia be prevented?
Safe sexual behavior and seeking proper health care can help keep people from becoming infected or re-infected with chlamydia and from experiencing chlamydia complications.
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Use condoms correctly every time you have sex.
Persons who engage in sexual behaviors that can place them at risk for STDs should use latex or polyurethane condoms every time they have sex. A condom put on the penis before starting sex and worn until the penis is withdrawn can help protect both the male and the female partner from chlamydia. When a male condom cannot be used appropriately, sex partners should consider using a female condom
Common methods of birth control, like the oral contraceptive pill or the contraceptive shot or implant, do not give women protection from STDs. Women who use these methods should also use condoms every time they have sex to prevent STDs.
Condoms do not provide complete protection from all STDs. Sores and lesions of other STDs on infected men and women may be present in areas not covered by the condom, resulting in transmission of infection to a new person.
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Limit the number of sex partners, and do not go back and forth between partners.
Practice sexual abstinence, or limit sexual contact to one uninfected partner.
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Get a screening test.
If you are young, sexually active, and do not use condoms correctly every time you have sex, you should be screened for chlamydia at least once a year. It has been shown that screening and treatment of women with chlamydia infection of the cervix reduces the likelihood of PID. All pregnant women should have a screening test for chlamydia.
If you think you are infected, avoid sexual contact, and see a health care provider immediately.
Any genital signs or symptoms such as discharge or burning during urination or an unusual sore or rash should be a signal to stop having sex and to consult a health care provider immediately.
If you are told you are infected, notify all your sex partners immediately.
If you are told you have chlamydia or any other STD and receive drug treatment, you should notify all of your recent sex partners so that they can see a health care provider and be treated. A sex partner needs treatment even if (s)he has no symptoms. This will reduce the risk that your partners will develop serious complications from chlamydia and reduce your risk of becoming re-infected. Do not have sex until both you and your sex partner complete your chlamydia drug treatment.
For more information
DSTD Web address http://www.cdc.gov/std//
CDC National STD Hotline
(800) 227-8922 or (800) 342-2437
En Espanol (800) 344-7432
TTY for the Deaf and Hard of Hearing (800) 243-7889National HPV and Cervical Cancer
Hotline (919) 361 - 4848
Resource Center www.ashastd.org/hpvccrc/National Herpes Hotline
(919) 361-8488
CDC NPIN
P.O. Box 6003 Rockville, MD 20849-6003
1-800-458-5231 1-888-282-7681
Fax 1-800-243-7012 TTY
www.cdcnpin.org/
info@cdcnpin.orgAmerican Social Health Association
P. O. Box 13827 Research Triangle Park, NC 27709-3827
1-800-783-9877
http://www.ashastd.org/
References
American Social Health Association. Sexually transmitted diseases in America: How many cases and at what cost? Research Triangle Park, NC, 1998.
Stamm, W.E. In: K. Holmes, P. Mardh, P. Sparling et al (eds). Sexually Transmitted Diseases, 3rd edition. New York: McGraw-Hill, 1999, 407-422.
