Chlamydia (genital infection)

Infectious agent

Chlamydia trachomatis serogroups D–K cause disease.

Identification

Clinical features

Most women with urethral or endocervical chlamydial infection are asymptomatic. Clinical manifestations may include vaginal discharge, dysuria and post-coital or intermenstrual bleeding. Less frequent manifestations include urethral syndrome (dysuria and pyuria), bartholinitis, perihepatitis and proctitis.

Complications and sequelae may result in chronic pelvic pain, infertility and ectopic pregnancy. Infections during pregnancy may cause preterm rupture of the membranes and preterm delivery. It can also cause conjunctivitis in the newborn and pneumonitis in the young infant.

The primary presentation of chlamydial infection in
males is urethritis but infection may be asymptomatic. Possible sequelae and complications of male urethral infection are epididymitis, infertility, Reiter’s syndrome and conjunctivitis. Receptive anal intercourse in men who have sex with men (MSM)

may result in chlamydial proctitis.

Method of diagnosis

Testing individuals at high risk of chlamydial infection is recommended. High risk individuals include those with a clinical presentation suggestive of chlamydial infection, individuals attending general practitioners for testing of sexually acquired infection (STI), those attending STI and family planning clinics and gay men’s health centres and partners of those already diagnosed with an STI. Laboratory investigations currently available are:

• cell culture (only in specialised laboratories)

• antigen assays including direct

immunofluorescence or enzyme immunoassay

• hybridisation assays such as the DNA probe

• amplification assays including PCR and ligase chain reaction (LCR).

The choice of test depends on the specimen type submitted, the cost of the test, the sensitivity and specificity of the test and the expertise and size of the laboratory.

Incubation period

The incubation period is poorly defined but is probably 7–14 days or longer.

Public health significance and occurrence

Infection with C. trachomatis has become a major public health problem because of the long term consequences of infection experienced predominantly by women. These include chronic pelvic pain, ectopic pregnancy and infertility. Rarely males may also become infertile. Chlamydia is the most commonly notified sexually transmissible bacterial disease in Victoria. It affects both genders. The annual number of notified cases has more than doubled since the early 1990s. Approximately 75% of infections are notified from individuals aged less than 30 years.

The prevalence of chlamydial genital infections in Australia has not been comprehensively established but it has been estimated to be 2.5 –14% in STD clinic patients, 5% in family planning

clients and up to 15% in commercial sex workers.

While the spontaneous cure rate has been estimated at 7.4%, immunity following infection is thought to be typespecific and only partially protective. As a result recurrent infections are common.

Risk factors for chlamydial infections include a relatively high number of sexual partners, a new sexual partner and lack of use of barrier contraceptive measures.

Endocervical C. trachomatis infection has also been associated with an increased risk of acquiring human

immunodeficiency virus (HIV) infection and may also increase HIV infectiousness.

Reservoir

Humans.

Mode of transmission

proportion of Transmission of C. trachomatis occurs primarily by sexual contact. Mother to baby transmission occurs when mothers colonised with C. trachomatis infect their babies as they are born vaginally. A high infections in women are asymptomatic resulting in untreated disease, ongoing transmission and an increased risk of sequelae.

Period of communicability

The period of communicability is unknown but may be months to years.

Susceptibility and resistance

Everyone is susceptible to infection.

Control measures

Preventive measures

Preventive measures include education about safe sex practices including use of condoms and early detection of infection by testing of those at risk.

Control of case

Azithromycin or doxycycline are used as first line antimicrobials to treat

chlamydial infection. Advice on the treatment of chlamydial infections can be found in Therapeutic guidelines:

antibiotic (Therapeutic Guidelines Limited) and the National management guidelines for sexually transmissible infections (Venereology Society of Victoria, 2002). Specialist consultation should be sought

for complicated or disseminated infections.

Control of contacts

Sexual partners of individuals with chlamydial infection should be examined and investigated then treated empirically.