DISEASE NAME:
Chlamydia
CATEGORY:
STIs
Chlamydia
Chlamydia is a curable sexually transmitted infection caused by the bacterium, Chlamydia trachomatis. It is the most common curable bacterial sexually transmitted infection in the western world and the numbers affected are likely to be underestimated as at least 70% of women and 50% of men who are infected may be asymptomatic.
For information, advice and support on sexual health visit: sexualwellbeing.ie
13,711 The number of Chlamydia notifications in 2023
258.9 The national notification rate per 100,000 population
Last updated: 26 March 2024
Case Definitions
Clinical Criteria
Any person with at least one of the following clinical forms:
Chlamydial infection non-LGV
At least one of the following ten:
— Urethritis;
— Epididymitis;
— Pelvic inflammatory disease;
— Acute salpingitis;
— Acute endometritis;
— Cervicitis;
— Proctitis;
— Purulent conjunctivitis;
— Reactive arthritis;
— Perihepatitis.
In newborn children at least one of the following two:
— Conjunctivitis;
— Pneumonia.
LGV
At least one of the following five:
— Urethritis;
— Genital ulcer;
— Inguinal lymphadenopathy;
— Cervicitis;
— Proctitis/proctocolitis.
Laboratory Criteria
Chlamydial infection non-LGV
At least one of the following three:
- Isolation of Chlamydia trachomatis from a clinical specimen.
- Detection of Chlamydia trachomatis by direct fluorescent antibody (DFA) test in a clinical specimen
- Detection of Chlamydia trachomatis nucleic acid in a clinical specimen
LGV
At least one of the following two:
- Isolation of Chlamydia trachomatis from a clinical specimen
- Detection of Chlamydia trachomatis nucleic acid in a clinical specimen
AND
- Identification of LGV stain.
- Possible case
Epidemiological Criteria
An epidemiological link by human to human transmission (sexual contact or vertical transmission)
Case Classification
A. Possible case
NA
B. Probable case
Any person meeting the clinical criteria with an epidemiological link
C. Confirmed case
Any person meeting the laboratory criteria
Last Updated: 22 November 2022
Information, Data and Reports for Chlamydia
Ireland’s specialist service for the surveillance of communicable diseases.