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It is possible that the main title of the report Chlamydia is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Chlamydia Trachomatis

Disorder Subdivisions

  • None

General Discussion

Chlamydia is a sexually transmitted bacterial infection with symptoms similar to those of gonorrhea. Until recently, chlamydia was identified primarily when a certain type of eye infection (trachoma) appeared as a symptom. Initially, the symptoms of chlamydia are usually mild and may not be recognized. In rare cases, chlamydia may have serious complications, if left untreated. Individuals who are sexually active and have multiple sex partners are especially at risk for this disease. Since many people with chlamydia do not realize that they have this infection, they may not seek treatment until serious complications occur. Meanwhile, they may have unknowingly spread the disease to others through sexual activity. Treatment with antibiotics is generally successful; however, prevention is the primary course of action.


Initially, chlamydia may have no noticeable symptoms. Symptoms that affect both males and females include inflammation of the tubes that carry urine from the kidneys to the bladder (urethritis), anal inflammation (proctitis), inflammation of the delicate membranes that line the eyes (conjunctivitis), inflammation of the throat (pharyngitis), and/or or a serious arthritis-like condition known as Reiter's syndrome. (For more information on Reiter's syndrome, choose "Reiter" as your search term in the Rare Disease Database).

When symptoms eventually appear in males, they usually consist of painful urination and a watery discharge from the penis. In some cases, this infection can cause an inflammation of part of the testicles (epididymitis), inflammation of the colon and rectum (proctocolitis), or inflammation of the prostate (prostatitis). Some affected males may experience rectal or urethral strictures, and/or sterility.

In females, chlamydia often begins as an infection or inflammation of the cervix (cervicitis). Itching and burning of the genitals, vaginal discharge, dull pelvic pain and bleeding between menstrual periods may also occur. The infection may then spread to the uterus and/or fallopian tubes. Some affected females may experience inflammation of the mucous membrane lining the uterus (endometritis), inflammation of a certain portion of the uterus (salpingitis), or inflammation of the cetain tissues (i.e., peritoneal capsule) of the liver and of the tissues around the liver (perihepatitis). The infection can subsequently cause infertility and, in some cases, presents the danger of the unusual implantation development of an embryo outside of the uterus (ectopic pregnancy). Inflammation throughout the female reproductive system (pelvic inflammatory disease [PID]) can be a consequence of delayed treatment of chlamydia.

Females who have chlamydial infections during pregnancy have a high risk of spontaneous abortion or stillbirth. Infants who contract the infection from their mothers at birth can get an infection or inflammation of the delicate membranes that line the eyes (conjunctivitis), inflammation of the throat (pharyngitis), and/or pneumonia. Some affected infants may experience chronic impairment of the respiratory system, affecting the ability to breathe. Prompt treatment of the infection in newborns is essential.


Chlamydia is a common infection caused by a bacterium known as chlamydia trachomatis. The disease is sexually transmitted (STD). In addition, the infection can also be transferred from infected mothers to newborn infants.

Affected Populations

According to public health officials, four million Americans report incidence of chlamydia each year. Chlamydia can affect both males and females of any age. However, there is a higher prevalence among individuals in their late teens and early twenties. It is estimated that one in six female adolescents and one in ten male adolescents are affected by chlamydia.

It is estimated that of the 155,000 infants born to women with chlamydia each year, 75,000 of then will develop an eye infection (conjunctivitis) and 30,000 eventually receive a diagnosis of pneumonia. It is further estimated that 60 to 80 percent of females and 10 percent of males with chlamydia have no symptoms. As a result, they do not seek treatment and may unknowingly spread the infection.

Chlamydia is one cause of pelvic inflammatory disease (PID) in females. More than 200,000 women are hospitalized in the United States each year with PID and one million are treated for the condition on an outpatient basis. An estimated 11,000 American women become sterile each year and 3,600 have an embryo implant and develop outside of the uterus (ectopic pregnancies) as a consequence of Chlamydia.

Standard Therapies


The diagnosis of chlamydia may be confirmed upon a thorough clinical evaluation, characteristic physical findings, a detailed patient history, and specialized laboratory tests (e.g enzyme-linked immunosorbent assay [ELISA]). The use of urinary analysis tests may also be helpful in diagnosing chlamydia.


Use of condoms during sexual activity can help limit the spread of chlamydia; however, medical authorities agree that the key is early detection. Once it is identified, chlamydia can be cured with antibiotics (e.g. tetracycline, erythromycin, aztithromycin). Antibiotic treatment usually lasts for seven to 21 days. Pregnant females or anyone who is being treated for another sexually transmitted disease should consider being tested for chlamydia. Sexually active individuals with multiple sex partners are at greater risk for contracting the infection.

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010


For information about clinical trials sponsored by private sources, contact:



Infectious Diseases: Sherwood L. Gorbach, John G. Bartlett, and Neil R. Blacklow, Editors; W.B. Saunders Company, 1992. Pp. 1633-41.

Cecil Textbook of Medicine, 19th Ed.: James B. Wyngaarden and Lloyd H. Smith, Jr., Editors; W.B. Saunders Co., 1992. Pp. 1732-34.

Harrison's Principles of Internal Medicine, 14th Ed.: Kurt J. Isselbacher, M.D. et al., Editors; McGraw-Hill, Inc., 1998. Pp.1055-62.

Mandell, Douglas and Bennett's Principles and Practice of Infectious Diseases, 4th Ed.: Gerald L. Mandell, M.D. et al., Editors; Churchill Livingstone Inc., 1995. Pp. 1676-93.


Community-Based Urine Screening for Chlamydia Trachomatis with a Ligase Chain Reaction Assay. J.M. Marrazzo et al.; Ann Intern Med (Nov 1 1997; 127). Pp. 796-803.

Chlamydia is not a Flower. It's a Sexually Transmitted Disease with Devastating Effects: Abbott Health Care Worldwide; Abbott Laboratories, Public Affairs, Dept. 383P, Abbott Park, IL 60064.

Centers for Disease Control Guidelines for Prevention and Control of Chlamydia Trachomatis Infections. Summary and Commentary. T.A. Bell et al.; Ann Intern Med (Apr 1986; 104(4)). Pp. 524-26.

Independent Associations of Bacterial Vaginosis and Chlamydia Trachomatis Infection with Adverse Pregnancy Outcome. M.G. Gravett et al.; JAMA (Oct 10 1986; 256(14)). Pp. 1899-1903.

Epidemiology and Therapy of Chlamydia Trachomatis Infections. W.R. Bowie; DRUGS (May 1984; 27(5). Pp. 459-68.


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For a Complete Report

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