Chlamydia Infections

Chlamydia is often referred to as a subgroup of bacteria. That is not fully correct; chlamydia is a quite special intracellular pathogen. Chlamydia group divides into many subgroups causing a lot of human diseases. Chlamydia behaves as a parasite, it attacks target cells and use them to multiplication. This is a lifestyle very similar to viruses. Classic bacteria (Streptococci, Staphylococci, etc.) attack body cells from outside. Chlamydiae are therefore quite exceptional and they are able to cause a variety of diseases according to affected body part (the eyes, urinary tract, lungs, etc.).


Chlamydia is most commonly transmitted by an unprotected sexual intercourse and it is the most frequent sexually transmitted disease (much more common than syphilis, gonorrhea and AIDS). Chlamydia presence is widespread in our population and taking into account that the majority of people have multiple sex partners in their lifetime (in many cases even per a week), it is not difficult to get infected. The infection may be transferred from an infected pregnant woman to the child. As Chlamydia is frequently present in the birth canal, the baby becomes infected during the childbirth. Some infection forms (e.g. lung, eye) may spread by exhaled droplets or common everyday objects (such as towels).


The symptoms depend of form of Chlamydia infection. We can distinguish the following:

Eye infection

Chlamydia trachomatis is worldwide of the most widespread causes of blindness. Infected eye is contagious and the infection can be transmitted to a healthy eye of different person, for example by a towel. Even pulmonary form of Chlamydia disease may cause eye infection when exhaled droplets with Chlamydia microorganisms get into the eye. Transmission from mother to fetal eye during the childbirth is also possible. The infection usually manifests as chronic conjunctivitis. When it is untreated it causes chronic changes including inversion of the eyelid and eye lashes begin to mechanically irritate the cornea and scar it. It is the corneal damage that is related to final blindness.

Pulmonary infection

Pulmonary infections care usually transmitted by exhaled or coughed up droplets containing Chlamydia that get inhaled by a healthy person. Mother-child transmission during the childbirth is again possible. Pulmonary form presents as a so-called atypical pneumonia. Sick person usually complaints about dry cough, elevated temperature (usually below 38°C) and suffers from general fatigue, muscle pain and joint pain. Chest X-ray finding is often much more serious than the symptoms would indicate. Newborn pneumonias can be easily fatal.

Genitourinary infection

This is the most known of Chlamydia infection. The transmission is by an unprotected intercourse and the course is a little bit different in males and females.


In males the infection usually affects the urethra causing urethritis. It may be asymptomatic but often it manifests with unpleasant burning pain during urination and it may be mistaken for gonorrhea. Any purulent discharge is however atypical for Chlamydia. Untreated infection of the urethra may spread to other parts of the male reproductive tract including prostate and epididymis resulting in painful prostatitis or epididymitis.


Female vaginal mucosa is very resistant to the infection and therefore the Chlamydia moves to the cervix causing its inflammation (cervicitis). From the cervix it can move deeper to uterus, fallopian tubes and ovaries causing deep pelvic infections. Female Chlamydia infections may cause very variable symptoms. Most often they are asymptomatic. It is insidious because asymptomatic disease may be more easily transmitted and can cause various complications (see below). Symptomatic forms include vaginal discharge, pain during intercourse and gynecological bleeding. Deep pelvic infections manifest by high fever and abdominal pain. Chlamydia infections in women have a higher risk of complications such as infertility. Chronic inflammation damages female reproductive tract and may disrupt its ability to nest the fertilized egg. Cervical damage may be related to premature births or even miscarriages. Infertility caused by chronic untreated Chlamydia infections may be incurable.

Joint disease

Joint are in Chlamydia infections affected mainly because of an overall inflammation caused by our own immune system. The joints are painful, reddish and swollen. In some people these Chlamydia arthritis may be a part of so-called Reiter’s syndrome (arthritis + urethritis + conjunctivitis).

Lymphogranuloma venereum

This is a special form of sexually transmitted Chlamydia infection. It is quite rare in USA an Europe but it is quite widespread in Africa and Asia. The infection starts as a painless pustule located on external genital. The infection spreads to local lymph nodes in the groin that become painfully swollen. Sometimes the inflammation forms fistula and the inflamed nodes empty their content creating ugly festering wounds. The infection is accompanied by fever and general malaise.


It is important to find any of the above mentioned symptoms that can lead us to clinical suspicion. Chlamydia presence may be confirmed by serology from blood tests (detection of antibodies against Chlamydia in the blood) or by making urethral or cervical swab. The swab is microbiologically examined to directly prove Chlamydia infection.


Protected sex is the best way of prevention of genitourinary form of infection. There is, however, a problem – as mentioned above, many cases of Chlamydia infection are asymptomatic. Even when both partners are faithful, there is no guarantee that they have not been infected by previous sexual partners. And protected sex is usually not preferred by stable couples.

Lung or ocular infection of the child transmitted from mother during the childbirth is preventable by microbiological examination of the pregnant woman’s cervix followed by antibiotics administration to the affected woman.


Chlamydia is sensitive against some types of antibiotics, especially macrolide antibiotics and tetracycline. Methods of administration and doses depend on actual case (type of infection, severity of the condition). Because of frequent sexual way of transmission, it is advisable to treat also the sexual partner(s).

Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources