Chlamydia (Chlamydia trachomatis)

Chlamydia is a sexually transmitted infection (STI) caused by the bacterium Chlamydia trachomatis. You can catch it by having unprotected sex. If left untreated, it may lead to serious long-term health problems.


Chlamydia bacteria can infect the cervix, rectum or the urethra. Sometimes, it can also infect the throat after performing oral sex. Infection can also spread to the eyes by touching an infected area and then touching the eye.

Most people infected with Chlamydia do not show any symptoms. As a consequence, it is under-diagnosed. However, if symptoms do occur, they usually appear 2 to 3 weeks after exposure.

In women, Chlamydia can cause abnormal vaginal discharge, vaginal bleeding between periods or during/after sex, abdominal or lower back pain, a burning sensation when urinating (peeing) and painful sex. In men, it can cause abnormal discharge from the penis, a burning sensation when urinating, itching around the opening of the penis and painful or swollen testicles.

Chlamydia can also cause problems getting pregnant or during pregnancy. These include miscarriage, preterm birth and low birth weight. Sometimes, the infection can be passed from mother to child during birth. This can cause a lung or eye infection in the child.


Chlamydia is transmitted during vaginal, anal or oral sex. It can be passed from an infected mother to her baby during childbirth. Anyone who is sexually active can be infected with Chlamydia. The risk of infection increases with the number of sexual partners.

Teenage girls and young women are more at risk. This is because their cervix is not fully matured. It is more susceptible to infection.


Chlamydia can be easily diagnosed with a urine sample. It can also be diagnosed with a swab taken from the cervix in females or urethra in males.

Chlamydia can be cured with antibiotics if found early. Once diagnosed, all sexual partners should be evaluated, tested and treated. Having untreated or multiple Chlamydia infections can increase a woman’s risk of serious reproductive complications. These complications include pelvic inflammatory disease and infertility.


Chlamydia can be prevented by consistently avoiding risky behaviours. Thus, avoid having multiple sexual partners and unprotected sex.

People should not have sex until both partners are tested and treated. Persons diagnosed should not have unprotected sex for 7 days after single-dose antibiotics or until completion of a multiple-dose treatment. This is to prevent the spread of infection to others.

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