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Volume: 26S3 - May 2000 Case Definitions for Diseases Under National SurveillancePDF Version
PREFACEThis document is the product of close cooperation between the Laboratory Centre for Disease Control, of Health Canada, and the communicable disease control epidemiologists in each province and territory. This cooperation is achieved through the Advisory Committee on Epidemiology (ACE), which is a forum for these provincial and territorial officials to advise their federal counterparts on matters related to the study and control of diseases. ACE decided in 1997 to review communicable disease surveillance in Canada. The review process resulted in this document. Diseases Under National Surveillance BASIC PRINCIPLES AND METHODS Goals
Quality If surveillance is considered necessary for any particular disease, then the surveillance must be carried out in such a way as to be of the highest epidemiologic quality. This implies the following:
We realize that full implementation will require a gradual phase-in period and will proceed at different rates in different jurisdictions. Reporting of Diseases Under National Surveillance In Canada, the reporting or notifying of diseases is mandated by provincial legislation, and the list of notifiable diseases differs by province/territory. Prior to 1990, each jurisdiction had its own set of case definitions, and comparability across jurisdictions was difficult, if not impossible. In March 1991, the Laboratory Centre for Disease Control (LCDC), in conjunction with the provincial and territorial epidemiologists, published disease-specific case definitions for diseases under national surveillance. For the first time, these case definitions provided standardized criteria for the reporting of cases under national surveillance. This second edition of case definitions should supersede the 1991 edition. In most instances, only confirmed cases are reported; a combination of clinical, laboratory and epidemiologic criteria is used to classify a confirmed case. For example, a confirmed case of a vaccine-preventable disease uses both a laboratory definition and an epidemiologic one (clinical illness in a person epidemiologically linked to a laboratory-confirmed case). Some case definitions include a brief clinical description; however, this information is intended for the purpose of classifying cases and should not be used for clinical diagnoses. Probable cases may be described to assist local public health authorities in carrying out their public health mandate, such as outbreak investigation and contact tracing. Physicians diagnosing a case of a specific (notifiable) disease report their clinical diagnosis with/without laboratory confirmation to local health authorities. These authorities are responsible for determining that the case meets the surveillance case definition before they officially report the case. Where there is uncertainty because data are missing or the results are inconclusive, it may be reported as a possible case, but the status must be made definite later; if not, the case must be deleted from the reporting system. The local health authority reporting the case collects all necessary epidemiologic data on it. All pertinent laboratory detections (from appropriate sites) must be reported to local health authorities, which will then contact the physician to determine whether the isolate/specimen came from a person who meets the case definition. If so, the case is reported and the necessary epidemiologic data are gathered by the health authority. The reporting of a case should be timely and need not be delayed until all epidemiologic data are available. Such data may be reported later and added to the original case report centrally. While local health authorities are encouraged to collect all information requested by the reporting system, when some items are not available the case should be reported with missing items listed as unknown. A case should never go unreported or deleted because of missing data. The only exception is when data to determine whether the case meets the case definition are missing. Such cases should not be reported. The "Core Set" of Variables The Advisory Committee on Epidemiology has agreed on "the necessary epidemiologic data" to be gathered for each reported case. This "core set of variables" includes province, disease, a unique identifier, age, gender, confirmed status (laboratory confirmed or epidemiologically linked), episode date, and geographic indicator. Reporting of Case-by-Case Data The Advisory Committee on Epidemiology has agreed to report case-by-case data, effective January 2000. Currently, some provinces/territories report aggregate data and some report case-by-case. Case-by-case reporting is "line-listed" information or, in other words, each case is reported on an individual basis with the core set of variables. All case reporting is non-nominal. The Protocol for Interprovincial/Territorial Notification of Disease
National Analysis and Reporting LCDC will publish annual surveillance summaries. Provisional data for the most recent reporting period will continue to be published each quarter in Canada Communicable Disease Report. Disease incidence and rates of infection will be available on LCDC's website under Notifiable Diseases On-Line and can be accessed at the following address: http://www.phac-aspc.gc.ca/dsol-smed/. TABLE OF CONTENTS BASIC PRINCIPLES AND METHODS CASE DEFINITIONS FOR DISEASES UNDER NATIONAL SURVEILLANCE Enteric, Food and Waterborne Diseases
Diseases Transmitted By Direct Contact and Respiratory Routes
Sexually Transmitted and Bloodborne Pathogens
Vectorborne and Other Zoonotic Diseases
Diseases Preventable by Routine Vaccination
Worldwide Potential Bioterrorism Agents
prepared by the Advisory Committee on Epidemiology and the Division of Disease Surveillance
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Last Updated: 2006-01-04 |  |
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