Causative organism Chlamydia trachomatis
Incubation period 2-60 days
How far to trace back 6 months
Usual testing method Nucleic acid amplification
Common symptoms

Asymptomatic (urogenital, anorectal, pharyngeal) in over 80% of people

Mucopurulent cervical discharge easily induced endocervical bleeding, urethritis with a mucoid or watery urethral discharge, dysuria.

PID- Pelvic pain, abnormal bleeding patterns (intermenstrual bleeding or post-coital bleeding), dyspareunia, fever, nausea, vomiting (see PID)

Epididymo-orchitis-scrotal pain, swelling, erythema (See Epididymo-orchitis)

Ano-Rectal - Anal discharge/pain, or bleeding

Eye - conjunctivitis

Throat - pharyngiitis

Likelihood of transmission per act of condomless intercourse <5%
Likelihood of long-term sexual partner being infected About two-thirds of partners will be infected
Protective effect of condoms High
Transmission by oral sex Low
Duration of potential infectivity

Urogenital infection: cervical infection can be sustained for years if left untreated, but on average 50% will clear a urogenital infection within 12 months.

Penile infection can be infected for months.

Anorectal infection: Can last for over 12 months if left untreated.

Limited data on duration of infectiousness overtime

Important sequelae

Cervical infection: PID/chronic pelvic pain/ infertility/ ectopic pregnancy

Penile infection: Epididymo-orchitis

Pregnancy and infants: Neonatal pneumonitis and conjunctivitis. Preterm labour and low birth weight.

Enhanced HIV transmission

Direct benefit of detection and treatment of contacts Reduces ongoing transmission and re-infection in index cases. Cervical re-infection substantially increases the risk of developing PID
Usual management of contacts

Counselling, clinical examination and testing for chlamydia.

People presenting as asymptomatic contacts of chlamydia should be tested and advised to await results. Consider presumptive treatment if there has been sexual contact within the past 2 weeks or when the person’s individual circumstances mean later treatment may not occur. As most people will test negative, routine presumptive treatment often leads to unnecessary antibiotic use.

Provision of patient-delivered partner therapy (PDPT) if appropriate.

If partners have epididymo-orchitis or PID, see sections in the STI Guidelines

Contact tracing priority High

Genital C. trachomatis infection is notifiable in all Australian states and territories by doctors or laboratories.

Genital C. trachomatis infection is not notifiable in New Zealand currently but voluntary laboratory notification occurs from most regions

Page last updated October 2022