Updates to the Canadian Notifiable Disease Surveillance System and its interactive website.

The Canadian Notifiable Disease Surveillance System (CNDSS) provides data on diseases that have been identified as priorities for public health monitoring and control. Several advances that have been made on Notifiable Diseases Online, the CNDSS interactive website, are consistent with the Government of Canada's commitment to Open Data. This article provides an update on changes in case definitions that have been made since the case definitions were last published in 2009, and describes updates that have been made to the interactive website since 2013. Changes were made to the case definitions of five diseases. For hepatitis C, the new case definition now distinguishes between acute and chronic infection. For cyclosporiasis, the probable case definition requires an epidemiologic link, with the clarification that this would likely be due to exposure to a common food source. For rabies, the probable case definition now refers to detection of rabies-neutralizing antibody instead of specific antibody titres. For Lyme disease, the revised confirmed and probable case definitions now identify five options for Lyme disease risk areas instead of endemic areas. For tuberculosis the revised case definition now includes nucleic acid amplification testing in addition to culture for diagnosis. The Notifiable Diseases Online website is an interactive tool that enables users to create customized figures and tables. Since a major redesign in 2013, numerous changes have been made to the look and feel of the site. Figures and tables can now be extracted as Excel or PDF files and large datasets are exportable into Excel files for further analysis. Case definitions in the national surveillance system will be updated as needed and its interactive website will continue to be improved and updated in response to user comments.

HIV in Canada-Surveillance Report, 2017.

BACKGROUND: Human immunodeficiency virus (HIV) is a global public health issue with an estimated 1.8 million people newly infected in 2017. OBJECTIVE: To provide a descriptive overview of reported cases of HIV in Canada by geographic location, sex, age group, exposure category and race/ethnicity, from 1985-2017, with a focus on the most recent data. METHODS: The Public Health Agency of Canada (PHAC) monitors HIV through the national HIV/AIDS Surveillance System, which is a passive, case-based system that collates non-nominal data voluntarily submitted and validated by all Canadian provinces and territories. Additional data sources presented here include data on immigration-related medical screening for HIV by Immigration, Refugees and Citizenship Canada and data on infants perinatally-exposed to HIV submitted by the Canadian Perinatal HIV Surveillance Program. Data were collated, tables and figures were prepared and descriptive statistics were applied by PHAC and validated by each province and territory. RESULTS: A total of 2,402 new HIV diagnoses were reported in 2017 in Canada; an increase of 3% compared with 2016 and an increase of 17.1% since 2014. The national diagnosis rate increased slightly, from 6.4 per 100,000 population in 2016 to 6.5 per 100,000 population in 2017. In 2017, while Ontario continued to account for the highest number (n=935) and proportion (38.9%) of reported HIV cases, Saskatchewan reported the highest provincial diagnosis rate (15.5 per 100,000 population). In 2017, the diagnostic rate for males at 9.9 per 100,000 population was higher than for females at 3.2 per 100,000 population. As in 2016, the 30-39 year age group had the highest HIV diagnosis rate at 14.8 per 100,000 population. The "gay, bisexual and other men who have sex with men" exposure category continued to represent almost half (46.4%) of all reported HIV cases in adults. In 2017, the absolute number of HIV-positive migrants entering Canada increased to a total number of 835 migrants. One mother-to-child HIV transmission was confirmed in a mother who did not receive any perinatal antiretroviral therapy and two transmissions were confirmed in mothers who did receive perinatal antiretroviral therapy. CONCLUSION: Similar to the annual changes that have been reported since 2014, the number and rate of reported HIV cases in Canada in 2017 increased slightly compared with 2016. Additional data and analysis are needed to determine the extent to which these findings reflect an increase in HIV transmission, an increase in HIV testing, changes in reporting practices and an increase in the number of HIV-positive people migrating to Canada.

Hepatitis C in Canada and the importance of risk-based screening.

Chronic hepatitis C (CHC) remains a public health issue affecting an estimated 220,000 individuals in Canada. In 2011, approximately 44% of those with CHC were unaware of their infection. Hepatitis C is infectious in origin, and if left untreated, can lead to significant morbidity and mortality in its chronic form, including liver cirrhosis, hepatocellular carcinoma and liver failure. These health outcomes are associated with comorbidities, adding a burden to the Canadian health care system. Recent advancements in the treatment of hepatitis C have changed the clinical landscape. In Canada, the prevalence of incident cases is higher in specific population groups. Injection drug use (IDU) currently accounts for the highest proportion of new hepatitis C virus (HCV) infection. It is unclear to what extent HCV infection through health care or personal services use contributed to current prevalent cases of CHC. The Canadian Task Force on Preventive Health Care (CTFPHC) is currently reviewing the evidence for different approaches to HCV screening and the benefits and harms of screening. Risk-based screening remains critical to detecting hepatitis C as knowing one's status has been linked to the cascade of care and improved population health outcomes. This article intends to highlight risk factors associated with the acquisition of HCV so that health care providers can screen, where appropriate, and detect CHC.

Chlamydia and lymphogranuloma venereum in Canada: 2003-2012 Summary Report.

BACKGROUND: Chlamydia continues to be the most commonly reported sexually transmitted infection in Canada. Lymphogranuloma venereum (LGV), caused by certain serovars of Chlamydia trachomatis, is becoming established in some populations in a number of Western countries. OBJECTIVE: To identify trends in reported cases of chlamydia and LGV in Canada from January 1, 2003 to December 31, 2012. METHODS: Notifiable disease data on chlamydia were submitted to the Public Health Agency of Canada by provincial and territorial epidemiological units and summarized at the national level by age and sex. Confirmatory testing for suspected LGV cases and serovar subtyping were performed by the National Microbiology Laboratory (NML). Where possible, provincial/territorial health authorities use a standardized national case report form to collect enhanced epidemiological data on each case and to submit the data to the Agency. RESULTS: Rates of reported cases of chlamydia increased by 57.6%, from 189.6 to 298.7 per 100,000 between 2003 and 2012. The rate of reported cases of chlamydia among females (383.5 per 100,000) was almost twice as high as that among males (212.0 per 100,000), although the highest relative rate increase occurred among males. In both males and females, the rates of chlamydia were highest in those aged 20 to 24 years. From 2004 to 2012, 170 cases of LGV were reported to the Agency by provincial health authorities (including 104 confirmed and 66 probable cases). In 2012, case reports were received on 12 confirmed and probable cases, compared to 38 laboratory-positive cases confirmed by the NML. CONCLUSION: In Canada, as in many countries, chlamydia rates have markedly increased over the last 10 years, in part due to improved diagnosis through nucleic acid amplification (NAAT) testing. Consistent with trends in Europe and other countries, LGV is emerging in Canada among men who have sex with men (MSM).

Gonorrhea in Canada: 2003-2012.

BACKGROUND: Gonorrhea is the second most commonly reported sexually transmitted infection in Canada. Between 1991 and 1997, Canada experienced a sharp decline in the rates of reported cases of gonorrhea, followed by a steady incline. OBJECTIVE: To identify trends in reported cases of gonorrhea in Canada from January 1, 2003 to December 31, 2012. METHODS: Notifiable disease reports were submitted to the Public Health Agency of Canada by provincial and territorial epidemiological units and data were summarized by age and sex. RESULTS: Between 2003 and 2012, the rate of reported cases of gonorrhea increased by 38.9%, from 26.0 to 36.2 per 100,000. Over this time frame, a greater relative rate increase was observed in females, though rates of gonorrhea increased in both sexes and across all age groups. In 2012, as in previous years, the rate of reported cases of gonorrhea was higher in males than females (41.4 vs. 31.0 per 100,000). Females between the ages of 15 and 24 years and males between the ages of 20 and 29 years accounted for the highest rates of gonorrhea in 2012. CONCLUSION: In Canada, as in many countries, gonorrhea is on the rise, especially in young adults. This increase in rates of reported cases is in part due to improved diagnosis through nucleic acid amplification (NAAT) testing and may also be affected by growing gonococcal resistance to many available treatments.

Infectious syphilis in Canada: 2003-2012.

BACKGROUND: In the 1990s, rates of reported cases of infectious syphilis were relatively low and were similar among males and females. In 2001, rates began to increase, particularly among males. OBJECTIVE: To identify trends in reported cases of infectious syphilis in Canada from January 1, 2003 to December 31, 2012. METHODS: Notifiable disease reports were submitted to the Public Health Agency of Canada by provincial and territorial epidemiological units and data were summarized by age and sex. RESULTS: Rates of reported cases of infectious syphilis increased by 101.0% between 2003 and 2012, from 2.9 to 5.8 per 100,000. Over this time frame, rates increased among males by 128.3% and decreased among females by 40.9%. In males, rates of infectious syphilis were highest among those aged 25 to 29; in females, rates were highest among those aged 20 to 24. CONCLUSION: In Canada, as in many countries, rates of reported infectious syphilis cases in males have markedly increased over the last 10 years.

Type-specific human papillomavirus infections and Pap test findings in Inuit and non-Inuit women in Nunavut, Canada.

OBJECTIVE: To determine the prevalence and distribution of type-specific human papillomavirus (HPV) infections and their association with cytological outcomes in women living in the Canadian territory of Nunavut. METHODS: Surveillance of type-specific HPV infection was conducted. Cervical specimens of all Inuit, First Nations and non-Aboriginal women in Nunavut who presented for a Pap test in any clinical setting between January 2008 and March 2009 were tested for HPV infection. The association between high-grade cervical lesions and HPV type was also examined. RESULTS: HPV results were available for 4,043 individual women (13 to 77 years). Of those with known ethnicity (N=4,033), 89.2% were Inuit, 0.4% were First Nations and 10.4% were non-Aboriginal. First Nations women were included in all analyses except those making comparisons by ethnicity, due to the small number of individuals in this group. Overall, 29.9% of women were found to be infected with HPV (any type) and 19.9% with any high-risk HPV (type 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 or 59). Most often, women were infected with HPV 16 (6.4%) followed by HPV 31 (3.1%). There were no statistically significant differences between Inuit and non-Aboriginal (reference group) women 20 years of age and older regarding the prevalence of any HPV (odds ratios (OR): 1.19, 95% confidence intervals (CI): 0.92-1.54), high-risk HPV (OR: 1.06, 95% CI: 0.78-1.44) or HPV 16 and 18 (OR: 0.81, 95% CI: 0.51-1.27). HPV 31 was the only type that was significantly more frequent among Inuit than non-Aboriginal women (OR: 3.95, 95% CI: 1.24-12.54). There was no difference in the overall occurrence of cervical abnormalities between non-Aboriginal and Inuit women (p-value = 0.17). HPV 16 was strongly associated with cervical dysplasia, being present in 50.9% of specimens with a high-grade lesion. CONCLUSION: HPV is a significant public health issue in the territory of Nunavut. The findings presented in this article are similar to those in other studies among Inuit women, with prevalence of HPV being higher than in studies conducted among non-Inuit women in other regions of Canada. These results provide a baseline of HPV prevalence that precedes the introduction of the Nunavut HPV Immunization Program in 2010 and will allow for future evaluation. The high prevalence of HPV infection among women living in Nunavut can be reduced through immunization and associated high-grade cervical abnormalities mitigated by regular cervical screening.

Hepatitis B surveillance in Canada: 2005-2012.

OBJECTIVE: To describe surveillance trends by age, sex and infection status of Hepatitis B (HB) virus in Canada between 2005 and 2012. METHODS: Data on acute and chronic HB cases reported to the Canadian Notifiable Disease Surveillance System were compiled at the national level to examine trends by age and sex over time. Time trends are presented from 2005 to 2012, corresponding to the availability of data differentiated by acute and chronic infection status. RESULTS: The rate of reported acute HB infections decreased from 1.0 to 0.6 per 100,000 between 2005 and 2012. Both sexes showed rate decreases over this time, although acute HB rates were consistently higher among males than females. The rate of reported chronic HB infections decreased from 14.1 to 12.0 per 100,000 between 2009 and 2012. These results are based on data in which infection status was specified. The proportion of unspecified cases in any given year may somewhat alter the results. CONCLUSION: This is the first time that trends in reported cases and corresponding rates of HB in Canada have been examined by acute and chronic infection status using national surveillance data. Canada continues to have a downward trend in HB rates across Canada, most notably in acute HB cases. Increasing national capacity to differentiate between acute and chronic HB will facilitate a more thorough understanding of trends in transmission and of the burden of HB infection in Canada.

Hepatitis C surveillance in Canada.

BACKGROUND: Hepatitis C is a highly transmissible virus that can lead to chronic liver disease. It continues to be a major public health concern in Canada. OBJECTIVE: To describe surveillance trends of reported cases of Hepatitis C virus (HCV) in Canada by age and sex from 1991-2012. METHODS: Cases of HCV reported to the Canadian Notifiable Disease Surveillance System were compiled at the national level. As most reported cases are not differentiated by acute or chronic HCV infection status, presented results are based on total HCV cases. Time trends are provided from 1991-2012, with a more detailed examination of age and sex patterns from 2005-2012. RESULTS: The rate of reported HCV infection increased sharply from 1991 (the year it was first notifiable) until 1998, when the highest overall rate of 66.9 per 100,000 was observed. From that time until 2012, rates of reported cases decreased in both sexes, but remained consistently higher among males than females. In 2012, the overall rate of reported HCV infection was 29.3 per 100,000. In younger age groups, rates among females were marginally higher, while males in older age groups (30 and above) exhibited substantially higher rates. CONCLUSION: This surveillance summary presents the longer-term trends in reported cases and corresponding rates of HCV in Canada using national surveillance data. Canada continues to experience a downward trend in HCV rates; however, the burden of infection will continue to increase as chronically infected individuals develop severe illness.

Sagittal sinus blood flow in the ovine fetus as a continuous measure of cerebral blood flow: relationship to behavioural state activity.

Superior sagittal sinus blood flow (Q(ss)) was studied over a 6-h period in nine chronically catheterized fetal sheep as a continuous measure of cerebral blood flow to determine the change in blood flow values and in measures of blood flow variability in relation to behavioural state activity. Mean Q(ss) was increased during the low voltage (LV)/rapid eye movement (REM) state compared to the high voltage (HV)/NREM state by approximately 25%, and was further increased during periods of LV/REM with fetal breathing movements. The increase in Q(ss) was abrupt and began at the transition to LV/REM, with the rate of change 2-fold greater than that during transition to HV/NREM, where the decrease in Q(ss) was gradual and began prior to the evident state change. Q(ss) showed considerable fluctuation, which tended to be greater during the HV/NREM state compared to the LV/REM state when analyzed using measures of longer term variability. Q(ss) thus provides for a continuous measure of cerebral blood flow in the ovine fetus, with the approximately 25% increase with change from the HV/NREM to LV/REM state similar to that previously reported using radioactive microspheres. The abrupt increase in Q(ss) at the transition to LV/REM versus the gradual decrease in Q(ss) before transition to HV/NREM would suggest that the state-related change in brain blood flow is better linked to the presence of the LV electrocorticogram and favours its active generation.