Sentinel Health Unit Surveillance System

T HE CANADIAN PUBLIC HEALTII SYSTEM lS CONSTANTLY challenged to develop disease prevention and control strategies for Canada. These strategies need to be developed using Canadian population-based data collected on the incidence of and the risk factors associated with selected diseases. Surveillance data can be used to determine the need for public health action. as well as to assess the effectiveness of public health strategies. The information gathered through epi demiological surveillance should be used for planning, implementing and evaluating public health programs (l). National surveillance activities in Canada are pri marily focused on the 45 notifiable diseases for which the Bureau of Communicable Disease Epidemiology, Laboratory Centre for Disease Control (LCDC). receives information monthly from provinces and territories. Information given for these diseases includes numbers of cases and a breakdown by sex and age group (2). Detailed information on individual cases is received from six provinces and the territories. Administrative data sets collected by Statistics Canada. hospital discharge databases (HMRI and Med ECIIO). provincial cancer registries. etc, have provided information on other diseases and health conditions. Information from all these sources has limitations in that its formal. quality and/or timeliness may not be sufficient for national surveillance needs. Sentinel systems used for surveillance are an effective public health tool. which has been used in other countries and has proven useful in the monitoring of many diseases (3). In Canada. sentinel physicians have been used in some provinces to monitor influenza ac-