Updated 25 June 2014

Chlamydia trachomatis

Chlamydia trachomatis is a common cause of bacterial sexually transmitted infection.


  • Chlamydia trachomatis can cause a variety of infections, including sexually transmitted infection (STI) as well as eye infections.
  • 80% of women with chlamydia are unaware that they have it.
  • Chlamydia can lead to severe complications if left untreated.
  • Gonorrhoea and chlamydia are often found together.

It is common for women with untreated chlamydia to develop pelvic inflammatory disease, an infection that spreads from the vagina and cervix to the uterus and fallopian tubes. Other complications include ectopic pregnancies and infertility. Men with chlamydia may develop epididymitis, an inflammation of the scrotal tubes that can cause sterility. Chlamydia is also associated with an increased incidence of pre-term birth. Babies born to mothers with chlamydia can be infected during passage through the infected birth canal. This can lead to pneumonia or eye problems such as conjunctivitis.

As chlamydia is hard to detect, especially in women, it is important to be tested regularly during routine annual visits and to practice safer sex to prevent transmission.


Chlamydia trachomatis is a bacterium which lives inside other cells (unlike most other bacteria). At one time, chlamydial organisms were thought to be large viruses, but they are now known to be more closely related to bacteria. The sexually transmitted disease is usually transmitted through vaginal or anal sex, or other intimate contact with the genitals, mouth or rectal area. Even if a person has no symptoms, they can still infect others with the disease.



In women
Women with an early infection of chlamydia usually do not have any symptoms. In some cases, the following symptoms can be present:
  • Vaginal discharge
  • Itching in the genital area
  • Mild pain and discomfort when urinating
  • Cloudy urine
  • Irregular menstrual bleeding
  • Lower abdominal pain
  • Fever
  • General tiredness
In men
  • Frequent urge to urinate or a burning sensation when urinating
  • Cloudy urine
  • A whitish yellow discharge from the penis
  • Redness or crusting at the tip of the penis

Lymphogranuloma venereum (LGV)

  • Genital ulcers, occuring one to two weeks after infection. These ulcers are usually fairly small and painless, and do not occur in every case of LGV
  • The ulcers often disappear on their own without treatment
  • One to two weeks later, enlarged inguinal lymph nodes appear, often associated with sore joints, headache and fever
  • The nodes can ulcerate, and can also cause either penile or rectal deformities in a small percentage of cases

Eye infections

  • Sometimes, infections of the eyes cause a raletively mild conjunctivits. This is the form seen in newborns infected via the birth canal, and can also sometimes be seen in adults. It seldom causes permanent damage to the eye even if untreated.
  • Trachoma is thought to result from repeated infection with the organism, and may also be a result of an abnormal immune response to the infection
  • Trachoma starts out as a conjunctivitis characterised by little follicles (white bumps) on the conjunctiva, and with repeated exposure and relapses, the cornea becomes progressively scarred and ulcerated, ultimately resulting in blindness.


The incubation period (the time between exposure to the bacteria and the beginning of symptoms) can be days or months. In many cases, especially in women who acquire the organism as a sexually transmitted infection, symptoms never appear. If there are symptoms, they are usually apparent one to three weeks after exposure.

  • Epididymitis (inflammation of the scrotal tubes)
  • Infertility
  • Infection of the prostrate (prostatitis)
  • Infection of the urethra (urethritis)
  • Infection of the lining of the eye (conjunctivitis)
  • Infection of the throat (pharyngitis)
  • Reiter's syndrome (an auto-immune arthritis-like condition)

  • Urethritis
  • Infection of the fallopian tubes (salpingitis)
  • Infection of the cervix (cervicitis)
  • Abnormal cells on the cervix (cervical dysplasia)
  • Infection of the lining of the uterus (endometritis)
  • Infection of Bartholin's glands (Bartholinitis)
  • Pelvic inflammatory disease, which can cause infertility
  • Ectopic (tubal) pregnancies
  • Pelvic abscess
  • Conjunctivitis
  • Pharyngitis
  • Reiter's syndrome
  • In isolated cases, perihepatitis (an infection of the area around the liver)

  • Miscarriage
  • Premature birth
  • Pre-term labour
  • Premature rupture of the membranes
  • Infection of the uterine lining (post-partum endometritis)

  • Conjunctivitis
  • Pneumonia
  • Ear infection
  • Infection of the urethra

Risk Factors

The risk of being infected with chlamydia from a single act of unprotected sex with an infected partner is estimated to be about 40% for women and 20% for men.

  • People who have unprotected sex
  • People who have multiple sexual partners
  • Sexually active adolescent women
  • People who have a history of STDs
  • Women who use intrauterine devices (IUDs) or take oral contraceptives
  • People who have gonorrhoea
  • Babies born to women with chlamydia

When to see a Doctor

  • Because many people are unaware that they have chlamydia, people who are sexually active should ask to be tested during all routine visits.
  • If there are any symptoms of chlamydia, immediate medical attention is needed.
  • If there are any symptoms of complications, such as high fever (37,7°C or higher), flu-like symptoms such as chills, backache, weight loss and diarrhoea, bleeding after intercourse, severe nausea, severe pelvic pain or recurring back pain.
  • Although conjunctivitis is usually viral, and usually mild, if you have conjunctivitis which does not appear to be resolving or there is an associated yellowish discharge from the eye, it would be advisable to visit your doctor.

Visit preparation

  • Be prepared to answer any questions about recent sexual activity.
  • Make a note of any symptoms if present.
  • If you are allergic to penicillin, you should inform the doctor.
  • Abstain from sexual intercourse while waiting for a medical examination.
  • All sexual partners should be notified as they will also need to be tested.


The doctor may perform a pelvic and genital examination, followed by an analysis of cervical fluid or penile discharge. The fluids are examined under a microscope with the aid of a substance that makes the bacteria glow. As many infections of the genitals or urinary system have similar symptoms, several tests for STDs and non-STD infections may be done. Diagnosis of the eye infection is done in a similar fashion - a smear is made of the discharge from your eye, and is examined under a microscope.



Chlamydia is easily cured if detected early and in uncomplicated cases the cure rate is 95%. It is usually treated with antibiotics such as tetracycline or doxycycline. Pregnant women should not be treated with tetracycline, but rather with erythromycin. Babies born to women with chlamydia will be treated with eye drops at birth. These eye drops contain antibiotics that should prevent further complications.


Sexual contact should be avoided until follow-up tests show no signs of infection.

Careful handwashing is essential to avoid transmission of the bacteria to the eyes.


  • Always use condoms during sex and foreplay to reduce the risk of infection. The female condom which is now available in South Africa can also reduce the risk of being infected.
  • As drugs or alcohol can interfere with a person's ability to make responsible decisions regarding protected sex, it is best to avoid sexual intimacy when intoxicated.
  • As chlamydia is often asymptomatic in women, it is extremely important to be tested during routine visits to the doctor.
  • Pregnant women or those who plan to have children should be tested for chlamydia.

Reviewed by Dr Andrew Whitelaw, MBBCh (Witwatersrand), MSc (UCT), FCPath (Micro) (SA) Senior registrar, Department of Microbiology, University of Cape Town and Groote Schuur Hospital.


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