Infectious diseases are a significant cause of illness and death in Canada, and, in addition to the sporadic cases of disease that usually occur on an ongoing basis, several outbreaks of these diseases occur each year. In a study carried out in Ontario using disease data for the years 2005 to 2007, 51 infections and infectious diseases were found to result in 729 lost health-adjusted life years (HALYs), over 44 deaths, and 58,987 cases of illness for every 100,000 people each year (Kwong et al, 2012). In another study, the number of cases of infections involving the blood-stream was estimated to be 79,000 to 94,000 per year, with 7,000 to 9,000 related deaths (Goto and Al-Hasan, 2013). Locally, infectious disease was identified as the primary cause of death in 2.4 to 4.4% of all deaths that occurred annually in the Wellington-Dufferin-Guelph area from 2000 to 2009 (Figure 1), fluctuating about the Ontario average of approximately 3.8%.
Several infectious diseases are reportable by law in Ontario, meaning that physicians and laboratories are required to report suspected and confirmed cases of these diseases to the local Medical Officer of Health. These include not only diseases with high mortality rates that do not usually occur in Canada such as hemorrhagic fevers, but also infectious diseases that commonly occur in Canada such as seasonal influenza and several sexually-transmitted infections. Reports of cases of reportable diseases are followed up by Public Health, usually by public health staff contacting each reported case to collect information about the case, to identify possible sources of the infection, to assess the risk posed by the case to others with whom the person may have come into contact and provide any necessary advice or education on preventing repeat infections and reducing the risk of spreading the infection to others. In 2011, WDGPH received and followed-up over 1500 reports of cases of illness, some outbreak-related, that occurred within the area served by the public health unit (the City of Guelph and the counties of Wellington and Dufferin).
This report summarizes the rates and trends of the reportable diseases most frequently reported to WDGPH over the five-year period 2007 to 2011. Each section of the report also provides an overview of each disease covered in that section, and highlight of the trends revealed by analysis of the data for that disease over the five-year period. This information can be used by public health staff and partners to review trends of the various diseases over the period in question, and to plan programs and services accordingly.