Giardiasis is a disease caused by the protozoa Giardia lamblia, also known as Giardia intestinalis. Symptoms of giardiasis include diarrhea, abdominal cramps, bloating, frequent, loose stools and weight loss. Symptoms may disappear and reappear over long periods of time. It is spread by consuming contaminated food or water or through close contact with an infected person. For more information, see the health unit's fact sheet on giardiasis.
Simcoe Muskoka
Ontario
Technical Notes
Simcoe Muskoka
The following graph shows the number of giardiasis cases in Simcoe Muskoka between 2000 and 2021. There have been between 29 and 76 cases of giardiasis reported in Simcoe Muskoka every year since 2000. In 2021, there were 62 cases reported in Simcoe Muskoka.
Ontario
The following graph shows the incidence rate of giardiasis in Simcoe Muskoka and Ontario between 2000 and 2021. The Ontario rate experienced an overall decrease during this time period. The Simcoe Muskoka rate is too variable to determine if there is a significant trend or if it is within the expected range for this disease. Prior to the pandemic, there was less variability in the Ontario rate because it is based on larger numbers of cases. The decrease observed in 2020 and 2021 should be interpreted with caution.
In 2021, the Simcoe Muskoka incidence rate was 10.1 cases per 100,000 population and Ontario’s incidence rate was 5.7 cases per 100,000 population.
More detailed data for Ontario and each health unit can be found on Public Health Ontario’s interactive Reportable Disease Trends in Ontario tool.
Technical Notes
There are many factors that influence how many cases are reported to the health unit, as explained on the Infectious Diseases page. It is unclear to what extent the global COVID-19 pandemic has influenced the reporting and spread of other infectious diseases – counts and rates of disease since 2020 should be interpreted with caution.
Provincial definitions classify cases as confirmed or probable based on clinical and/or laboratory diagnostic criteria. The provincial case definition for giardiasis changed in April 2009 to include a definition for probable cases whereas before there was no such classification. The definitions of confirmed and probable cases from 2009 onwards are comparable to confirmed cases before 2009.
In 2019, the definition of a confirmed case was changed to require an individual to present with clinically compatible signs and symptoms. Prior to 2019, an individual did not need to have clinical signs and symptoms to be classified as a confirmed case.
Page last updated August 19, 2022