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Chlamydia trachomatis infections

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Reporting Obligations

Individuals who have or may have chlamydia shall be reported to the local Health Unit. For community health professionals testing and treating chlamydia and gonorrhea infections, please review the following memo.

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Aetiologic Agent

Chlamydia trachomatis is an obligate intracellular bacterium causing genital infections and other forms of infections including chlamydial conjunctivitis and pneumonia.

Clinical Presentation

Chlamydia infection is often asymptomatic including pharyngeal and rectal infections. If symptoms are present in rectal infections individuals often display rectal discharge and pain.

Males may present with urethral discharge, dysuria and frequency, non-specific urethral symptoms such as redness, itching, and swelling.

Females may present with cervical infection that includes the following signs and symptoms: a mucopurulent endocervical discharge with edema, dysuria, dyspareunia, erythema, and easily induced endocervical bleeding.

Complications and sequelae include salpingitis pelvic inflammatory disease with subsequent risk of infertility.

Can present as chlamydial pneumonia and conjunctivitis (Ophthalmia neonatorum) in infants.

Modes of Transmission

Sexual contact via oral, vaginal, cervical, urethral or anal routes; in children, exposure to infected genitals (consider the possibility of sexual abuse in these cases); newborns: during delivery from infected mother.

Incubation Period

From time of exposure to onset of symptoms is 2–3 weeks, but can be as long as 6 weeks.

Period of Communicability

Unknown; may extend for months or longer if untreated, especially in asymptomatic persons; re-infections are common; effective treatment ends infectivity.

Risk Factors/Susceptibility

General susceptibility. Risk factors for transmission include:

  • Sexual contact with a chlamydia-infected person.
  • A new sexual partner or multiple partners in the past year.
  • Previous STIs.
  • Vulnerable populations (e.g., people who use injection drugs, incarcerated individuals, sex trade workers, street-involved youth etc.)

Diagnosis and Laboratory Testing

Chlamydia trachomatis detected in an appropriate clinical specimen (e.g., urogenital tract, rectal specimen). Refer to the Canadian Guidelines on Sexually Transmitted Infections, evergreen edition and Bacterial STI Testing: Quick Reference, March 2019 and additional resources (below).

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Treatment and Case Management

Treatment is determined as per attending health care provider. Refer to the Canadian Guidelines on Sexually Transmitted Infections, evergreen edition for treatment information. Individuals should abstain from unprotected sexual activity until treatment is complete (i.e., after completion of a multiple-dose treatment or for seven days after single-dose therapy). Re-infection is common (e.g. after 28 days).

Provide education about and promote safer sex practices. Repeat testing is recommended 6 months post-treatment, as re-infection risk is high.

Patient Information

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Additional Resources

Public Health Ontario. “Bacterial STI Testing: Quick Reference, March 2019.”

Public Health Agency of Canada. “Canadian Guidelines on Sexually Transmitted Infections, evergreen edition.”

Planned Parenthood. “Chlamydia.”


Ministry of Health and Long-Term Care, Infectious Diseases Protocol, 2022.