Executive Summary

Sexually transmitted infections (STIs) continue to be a significant and increasing public health concern in Canada. Reported rates of chlamydia, gonorrhea and syphilis have been rising since 1997, and this upward trend is continuing unabated. This report outlines the trends in these three nationally notifiable STIs, providing an overview of the descriptive epidemiology of these infections in Canada with a focus on the past decade. Longer term secular trends are presented for context.

Chlamydia continues to be the most commonly reported STI in Canada. Reported rates of chlamydia infections have increased by 80.2% over the past decade. A steady increase in reported rates has been observed in both genders and across all age groups, with the highest relative increase among males. However, females remain disproportionately affected by chlamydia infection. In 2008, the reported rate among women was almost twice as high as that of their male counterparts, and 86.7% of reports among females were for those under the age of 30. Geographic variation was observed with the highest chlamydia rates reported in Nunavut, the Northwest Territories and Yukon.

The overall reported rate of gonorrhea increased by 116.5% over the past decade. The majority of reported cases were in those under 30 years of age. Females between the ages of 15 to 24 and males between the ages of 20 to 24 accounted for the highest reported rates of gonorrhea. The older male population, particularly those over the age of 60, experienced a dramatic rise in the rate of reported cases since 1999, although reported rates remain low in this group compared to other age groups. Like chlamydia, the distribution of reported cases of gonorrhea varies geographically across Canada. The highest reported rates occurred in the Northwest Territories and Nunavut, followed by Manitoba and Saskatchewan.

The overall reported rate of infectious syphilis increased by 568.2% over the past decade. Reported rates of infection were highest among males aged 25 to 39; among females, highest rates were reported among those 20 to 24 years old. During this time period, outbreaks were reported in Vancouver, Edmonton, Calgary, Winnipeg, Toronto, Ottawa, Montreal, and the Yukon among men who have sex with men and among heterosexual populations. Most recently, during 2008–2009, outbreaks have been reported in the Northwest Territories and Nova Scotia.

 

Reported Cases and Rates (per 100,000 population) of Chlamydia, Gonorrhea, and Infectious Syphilis, 1999 and 2008

	Chlamydia		Gonorrhea		Infectious Syphilis
	Cases	Rates	Cases	Rates	Cases	Rates
1999	42,141	138.2	5,381	17.6	191	0.6
2008	82,919	248.9	12,723	38.2	1,394	4.2

 

Comparisons of reported STI rates to those of other western regions such as the United States, Australia, and the United Kingdom demonstrate that the observed increase in bacterial STIs is not unique to Canada, along with other similarities in trends. In all four countries, chlamydia is the most commonly reported STI and affects predominantly younger age groups, especially females. Gonorrhea rates in each country are highest in males aged 20 to 24. Across countries, males have the highest rates of infectious syphilis, reflecting the recent occurrence of outbreaks among men who have sex with men (MSM).

Report on Sexually Transmitted Infections in Canada: 2008

Chlamydia, gonorrhea, and syphilis are sexually transmitted infections of public health significance included on the list of nationally notifiable diseases in Canada. Resultant surveillance data are analyzed and summarized periodically, focusing on changes over the past decade. To provide context for the past 10 years, a longer secular trend is presented for each disease in the introduction. Several observations for 2008 are noteworthy.

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