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[Sexual Health and Sexually Transmitted Infections]

2004 Canadian Sexually Transmitted Infections
Surveillance Report: Pre-Release

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Introduction

To facilitate a release of key national sexually transmitted infections (STI) data, the following tables have been updated to 2004 using data submitted by all provinces and territories in Canada. Data included in this pre-release report should be considered provisional until publication of the 2004 Canadian Sexually Transmitted Infections (STI) Surveillance Report

Highlights

Reported cases of chlamydia, gonorrhea and infectious syphilis have been steadily increasing since 1997 in Canada. While some of the increase in reported chlamydia cases is attributable to improved testing methods, regional outbreaks of syphilis and gonorrhea have occurred. Factors that help to explain the rising trend in reported bacterial STI will be explored in the forthcoming surveillance report for 2004.

Chlamydia

Chlamydia is the most commonly reported STI in Canada.
Nearly 63,000 cases of chlamydia were reported in 2004, the highest number since chlamydia became reportable in 1990.
From its lowest point in 1997, rates have increased over 70%, from 113.9 to 197.1 per 100,000 in 2004.
- Over the same time period, rates in males have more than doubled (from 58.7 to 129.5 per 100,000); rates in females have increased by 57% (from 167.8 to 263.2 per 100,000).
Females account for over two-thirds of the reported cases. This is a more equitable distribution than in 1997, when females accounted for almost three-quarters of reported cases. The shift may be partially explained by the introduction of a non-invasive testing method, encouraging more males to consent to testing.
Adolescents and youth continue to be disproportionately affected: over two-thirds of the reported cases of chlamydia are in the 15-24 year old age group (Table 1.1 and Table 1.2).
As many chlamydia infections are asymptomatic and remain undiagnosed, the reported numbers underestimate the true burden of disease.

Gonorrhea

Gonorrhea is the second most commonly reported STI in Canada.
The reported rate has almost doubled from 1997 to 2004, from 14.9 to 28.9 per 100,000.
In contrast to chlamydia, males account for more than 60% of the reported cases.
The age distribution between males and females differs.
- Among females, 15-24 year olds are disproportionately affected. They accounted for 70% of cases in 2004.
- The burden of disease is distributed across a broader age range in males. Young adults (20-29 years old) represent over 40% of all cases in males, but 30-39 year olds also account for a substantial proportion (20%) of reported gonorrhea infections.
The gender disparity in gonorrhea may reflect outbreaks and increased transmission among populations such as men who have sex with men (Table 2.1 and Table 2.2).

Infectious Syphilis

In Canada, ‘infectious' syphilis is defined as primary, secondary, and early latent (< 1 year) infections.
The elimination of infectious syphilis in Canada was identified as an imminent goal as recently as 1996. However, rates have risen steadily since that time and in 2004, the national infectious syphilis rate was almost 9 times the rate reported in 1997 (3.5 vs. 0.4 per 100,000).
The reported rate among males in 2004 was more than 15-fold higher than the rate in 1997 (from 0.4 to 6.3 per 100,000); the reported rate among females more than doubled during this time period (from 0.3 to 0.8 per 100,000).
This increase has been disproportionately higher amongst males, who account for almost 90% of all reported cases in 2004.
Males over 30 appear to be driving the increase: 82% of male cases and 72% of cases overall are among men aged 30-59 years.
The reported cases are more widely distributed across age groups in females with 48% of cases among women aged 20-29 and 43% among those aged 30-59 (Table 3.1 and Table 3.2).