Chlamydia Infection: Prevalence, Serotypes, Symptoms,Causes,Tests & Treatment


Chlamydia trachomatis, a small gram-negative obligate intracellular bacterium, is the most common cause of bacterial sexually transmitted disease (STD) in both men and women in many countries of the world. However, it is largely under-diagnosed in Nigeria due to unavailability of equipment for testing.


There are 18 serovars associated with different medical conditions

Serovars A, B, Ba, C- Causes trachoma, a serious eye disease endemic in Africa and Asia that is characterized by chronic conjunctivitis and consequent blindness if left untreated

Serovars D to K- Causes genital tract infection

Serovars L1, L2, L3- Causes Lymphogranuloma Venerum which is associated with genital ulcers in tropical countries


Chlamydial genitourinary disease is caused by sexual transmission through oral, vaginal and anal intercourse.

Factors that increase the risk of getting chlamydial infection include; multiple sexual partners or single unfaithful sexual partner, low/intermediate education and socioeconomic status, low condom use, sexually active age group (19-25years), genetic predisposition, presence of other sexually transmitted infection.


Data is scanty due to low testing. A study conducted in Enugu showed prevalence of 29.4% out of 286 females. While a study done in Kano showed a prevalence of 8.7-10.7%.


It occurs 1-3weeks after exposure to the bacteria in an infected sexual partner. Disease manifestations in men are different from those in women due to the difference in the anatomy of their genital tracts


1. Some men may have no symptoms.

2. In those with symptoms, the commonest is urethritis which is characterized by painful urination and discharge of pus from the opening (urethra) in the penis. It is the commonest cause of non-gonococcal urethritis

3. Proctatitis: which involves discharge of pus from the anal opening with pain on defecation. This occurs only in men sleeping with men

4. Epididymitis/epididymo-orchitis: painful swelling noticed in the scrotum and worsened when scrotum is lifted up together with fever and painful urination.

5. Prostatitis: which involves painful urination, pain in the lower abdomen, painful ejaculation, fever e.t.c

6. Reactive arthritis (formerly called reiter`s triad): which consists of a classical triad of urethritis, arthritis and conjunctivitis


1. Urethritis: Similar to that in men and is characterized by painful urination and discharge of pus from the opening (urethra) in front of the vagina

2. Cervicitis: Discharge from the vagina, abnormal vaginal bleeding, easy bleeding of the cervix during sexual intercourse or when touched by a finger, painful intercourse

3. Pelvic imflammatory disease which causes lower abdominal pain, fever and vaginal discharge

Chlamydia infection
A woman with chlamydia infection

4. Pregnancy: Untreated chlamydia infection can increase the risk for premature rupture of the membranes and low birth weight

5. Reactive arthritis (formerly called reiter`s triad): which consists of a classical triad of urethritis, arthritis and conjunctivitis


Samples are collected through different means and subjected to different tests. For women, a vulvovaginal swab in which the woman inserts a swab about 5cm into her vagina and rotates gently for 10-30 seconds is the best.

An endocervical swab can be done in a doctor`s office when the doctor passes an instrument called speculum into the vagina and the swab inserted straight into the cervix.

For men, a swab of urethral discharge and first catch (early morning urine) sample can also be collected. Swab of the rectum and oropharynx can also be done in people who engage in oral or anal sex. The tests that can be done with all these samples include:

1. Nuclear acid amplification test (NAAT): Nucleic acid amplification (NAAT) methodology consists of amplifying C. trachomatis DNA or RNA sequences using polymerase chain reaction (PCR), transcription-mediated amplification (TMA), or strand displacement amplification (SDA). It is now the gold standard. Used for both screening and diagnosis

2. Culture: Culture methods are now limited to research and reference laboratories due to its expense. Culture should be used routinely only in cases of forensic investigation (eg, rape, child abuse)


Antibiotics is the mainstay of treatment and chlamydia is curable. Azithromycin or doxycycline are the antibiotics of choice. Erythromycin and amoxicillin can also be used in pregnant women due to safety profile.


Perihepatitis (Fitzhugh-Curtis syndrome), tubo-ovarian abscess, urethral stricture, infertility or subfertility, ectopic pregnancy, pelvic inflammatory disease, and tubal blockage


Ikeme AC et al. Seroprevalence of Chlamydia Trachomatis in Enugu, Nigeria. 14(2):2011. Nigerian Journal of Clinical Practice. Pg 176-180

Nnwakwo EO, Magaji NS. Prevalence of chlamydia trachomatis infection among patients attending infertility and sexually transmitted disease clinic in kano, north western Nigeria.

14(3):2014. African Health Science. Pg 672-676

Written by: Oteme Favour (MBBS,Benin)


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