Medical expert of the article

Internist, infectious disease specialist

New publications

Chlamydia in children

Alexey Kryvenko, medical expert
Last reviewed: 05.07.2025

All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.

We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.

If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.

Chlamydia in children is a group of anthroponotic and zoonotic diseases caused by pathogens of the genus Chlamydia, with granulomatous lesions of the mucous membranes of the eyes, respiratory tract, genitourinary system, regional lymph nodes, joints, liver and spleen, with frequent involvement of other internal organs in the pathological process.

ICD-10 code

A70 Infection caused by Chlamydia psittaci.
A71 Trachoma.
A71.0 Initial stage of trachoma.
A71.1 Active stage of trachoma.
A71.9 Trachoma, unspecified.
A74 Other diseases caused by chlamydia.
A74.0 Chlamydial conjunctivitis (keratotrachoma).
A74.8 Other chlamydial diseases (chlamydial peritonitis).
A74.9 Chlamydial infection, unspecified.

Causes of Chlamydia in Children

The genus Chlamydia includes three species of obligate intracellular bacteria: Ch. Trachomatis, Ch. psittaci and Ch. pneumoniae. The species Ch. Trachomatis and Ch. pneumoniae are primary pathogens for humans, and the species Ch. psittaci are primary pathogens for animals. In terms of biological properties, chlamydia occupy an intermediate position between viruses and bacteria. Elementary particles are round, 250-350 nm in diameter, reproduce well intracellularly, and contain RNA and DNA.

In human pathology, the most important species is Ch. Trachomatis, which includes 15 serovars. These are the causative agents of trachoma, conjunctivitis with inclusions (paratrachoma), urogenital pathology (urethritis, cervicitis, etc.), pneumonia in newborns and infants, the venereal form of Reiter's syndrome, inguinal lymphogranulomatosis, etc.

The species Ch. psittaci includes 13 serovars - pathogens of diseases in animals (ornithosis) and lower mammals (enzootic abortions, pneumonia, arthritis, gastroenteritis, meningoencephalitis, etc.), which can be transmitted to humans, causing various forms of pathology.

The species Ch. pneumoniae was officially registered only in 1989. So far, only one biovar is known; it causes respiratory pathology in young children, mainly small-focal and interstitial pneumonia.

trusted-source [ 1 ], [ 2 ]