Chlamydia and LGV guide: Etiology and epidemiology

Etiology and epidemiology of Chlamydia trachomatis infections (including lymphogranuloma venereum (LGV)).

On this page

Etiology

Chlamydia is a bacterial infection caused by C. trachomatis genotypes D to K.

LGV is a bacterial infection caused by C. trachomatis genotypes L1, L2 or L3.

Epidemiology

Chlamydia

Chlamydia is the most common reportable sexually transmitted infection (STI) in Canada. Rates have been increasing steadily since 1997Footnote 1. Chlamydia may be under-detected because the majority of people with an infection are asymptomaticFootnote 2Footnote 3 and empiric treatment may be given without laboratory testing.

Males may be under screened due to infrequent health visitsFootnote 3Footnote 4Footnote 5. High-risk people may also be under screened.

Sexually active youth and young adults are disproportionately represented in case reports for chlamydia. Between 2010 and 2019, chlamydia infections were most commonly reported in females when compared to males. However, rates are increasing faster in males than females, narrowing the gap in rates between the sexesFootnote 6.

LGV

LGV is relatively rare. Prior to 2004, most Canadian cases were identified in travellers returning from endemic regions of Africa, Southeast Asia, the Caribbean and Latin AmericaFootnote 7. Since 2004, there have been LGV outbreaks in Canada, mainly in gay, bisexual and other men who have sex with men (gbMSM).

National enhanced surveillance of LGV was carried out from 2004-2012. During this time, 104 confirmed and 66 probable cases were reported to the Public Health Agency of Canada (PHAC) by provinces and territories. Confirmed cases were reported from Quebec, Ontario, British Columbia and Alberta; probable cases were reported from these provinces as well as from Nova Scotia.

More information

Local epidemiological information: Consult with your public health unit.

National epidemiological information:

Global epidemiological information: World Health Organization Report on global sexually transmitted infection surveillance

References

Footnote 1

Choudhri Y, Miller J, Sandhu J, Leon A, Aho J. Chlamydia in Canada, 2010-2015. Can Commun Dis Rep 2018 Feb 1;44(2):49-54.

Return to footnote 1 referrer

Footnote 2

Farley TA, Cohen DA, Elkins W. Asymptomatic sexually transmitted diseases: the case for screening. Prev Med 2003 Apr;36(4):502-509.

Return to footnote 2 referrer

Footnote 3

Marrazzo JM, Whittington WL, Celum CL, Handsfield HH, Clark A, Cles L, et al. Urine-based screening for Chlamydia trachomatis in men attending sexually transmitted disease clinics. Sex Transm Dis 2001 Apr;28(4):219-225.

Return to footnote 3 referrer

Footnote 4

Chen MY, Donovan B. Screening for genital Chlamydia trachomatis infection: are men the forgotten reservoir? Med J Aust 2003 Aug 4;179(3):124-125.

Return to footnote 4 referrer

Footnote 5

Andersen B, Olesen F, Moller JK, Ostergaard L. Population-based strategies for outreach screening of urogenital Chlamydia trachomatis infections: a randomized, controlled trial. J Infect Dis 2002 Jan 15;185(2):252-258.

Return to footnote 5 referrer

Footnote 6

Public Health Agency of Canada. Report on sexually transmitted infection surveillance in Canada, 2019. Government of Canada. 2021.

Return to footnote 6 referrer

Footnote 7

Mabey D PR. Lymphogranuloma venereum. Sex Transm Infect 2002;78:90-92.

Return to footnote 7 referrer

Page details

Date modified: