Notifiable Diseases Online

From Public Health Agency of Canada

Notifiable Diseases Online is an interactive website that enables users to explore annual data from the Canadian Notifiable Disease Surveillance System (CNDSS). The CNDSS monitors trends in nationally notifiable diseases, infectious diseases that have been identified collectively by the federal, provincial and territorial governments as priorities for monitoring and control. Since 1987, the list of nationally notifiable diseases has been periodically reviewed using established criteria. ^{Footnote 1 Footnote 2 Footnote 3}

Provinces and territories voluntarily report annual notifiable disease data to the federal government, via CNDSS or to disease-specific program areas at the Public Health Agency of Canada. In most cases, disease-specific programs share these data with the CNDSS, so that national disease counts and rates can be reported directly on Notifiable Diseases Online. This site can be used to explore trends in reported cases of nationally notifiable diseases since 1924, where data are available.

Using Notifiable Diseases Online

Notifiable disease charts

This website provides data on nationally notifiable diseases including the counts and rates of reported cases, data limitations and disease descriptions. Users have the option to view simple pre-built charts, custom charts, or perform large data extracts. Output includes a graphical representation of the data, based on the type of chart and parameters selected. The source data table, limitations of the data and descriptions for the selected notifiable disease(s) are also provided.

There are three options for downloading query results under the Query Filters section:

1. The Print PDF button produces a printable PDF document that contains the chart, source data table, data limitations and disease descriptions.
2. The Excel export button creates a Microsoft Excel (.xls) workbook containing the data limitations and disease descriptions in the Notes tab and the data table in the Data tab.
3. The CSV export button creates a comma-separated values (.csv) data file for ease of import into other software. This export creates two files: the first contains the data, and the second contains relevant notes pertaining to the exported data. In this export, cells for which no data are available will be blank.

Users can also view the list of nationally notifiable diseases, including case definitions.

Data notes and limitations

General notes

• Cases reported may not represent all of the cases in the population. Underreporting may occur for the following reasons:
  • Not all people who are infected will seek medical attention;
  • Reporting of diagnosed cases is not complete;
  • Diagnostic tests may result in a false negative;
  • Case definitions of reporting jurisdictions may differ from the national case definition for a particular disease;
  • Not all provinces or territories are able to report on all diseases in every year; this does not necessarily mean that there have been no cases of the selected disease in that jurisdiction;
  • Some nationally notifiable diseases are not reportable at the provincial/territorial level. In those cases, provinces and territories do not provide data to CNDSS.
• Limitations specific to the selected disease(s) are listed under the related query output and are important for interpretation of the data shown, due to limitations of both the data and the chart functionality.
  • This also includes a colour-coded grid that displays the reporting pattern of jurisdictions by year included in the output.
• Tables in the query results will have an entry of N/A if they were not nationally notifiable in the years(s) selected, were not reported by any province/territory in the selected year(s), or where disaggregation by age and sex may not be available or relevant.
• Diseases that were previously nationally notifiable are not available for selection in the notifiable disease charts if they were notifiable for a short period, they were rare while notifiable, or completeness and/or consistency of reporting was poor.
• Disaggregations by age group and sex are available from 1991 onwards.
• Only confirmed cases of disease are included, unless otherwise specified.
• Due to periodic updates of the historical surveillance data, counts and rates for a particular disease and year may change over time.
• Caution: Data for the years 2020 and 2021 should be interpreted with caution due to the possible impacts of the COVID-19 pandemic on public health surveillance and access to healthcare services in Canada.

Denominators used for rate calculations

Congenital and/or perinatal diseases:

• 1979 to 1990: Because live birth data were not available for this period, estimates were calculated using the proportion of low birth weight births in the given years from, “Low birth weight (less than 2,500 grams) and borderline viable birth weight-adjusted low birth weight (500 to less than 2,500 grams), by sex, Canada, provinces and territories, annual”. Source: Statistics Canada, CANSIM Table 102-4005 (Accessed 2013-08-01).
• 1991 to 2022: Live births from “Statistics Canada. Table 17-10-0059-01 Estimates of the components of natural increase, quarterly. CANSIM (database).” (Accessed 2024-02-26)
• Please note that the number of births is final up to December 2021, updated from January 2022 to December 2022.

All other diseases:

• 1924 to 2020: Final intercensal population estimates were used for calculating the appropriate denominators for rate calculations. The intercensal population estimates are final and remain stable over time. Source: Statistics Canada, Demography Division
• 2021 to 2022: Population estimates used to calculate denominators for the years
  2021 to 2022 were as follows (Source: Statistics Canada, Demography Division):
  • 2021: Final postcensal population estimates
  • 2022: Updated postcensal population estimates
• Population estimates are subject to updates over time.