Burden of Recreational Water Illness Due to Exposure to Cyanobacteria and Their Toxins in Freshwater Beaches in Canada

Condition(s) studied

Investigational drug(s) / intervention(s)

Cyanobacteria exposure during water contact: Cyanobacteria levels in beach water among participants who report water contact in the beach survey

Study summary

Swimming and other recreational water activities at public beaches are increasingly popular leisure activities among Canadians. However, harmful algal blooms caused by blue-green algae (i.e., cyanobacteria) have also been increasing reported at Canadian public beaches in recent years. These algal blooms can cause various acute illnesses among recreational water users through ingestion, inhalation of aerosols, or skin contact with contaminated water. In addition, blue-green algae blooms and their toxins can cause illnesses in pets and wildlife. Currently, baseline data are lacking on the risk of recreational water illness from exposure to blue-green algae blooms in Canada. This study will identify the burden of recreational water illness among recreational water users at four targeted beach sites in Ontario, Manitoba and Nova Scotia, over a two-year period. A prospective cohort study design will be used. The investigators will determine the risk of acquiring acute illness outcomes in recreational water users, as well as their pet dogs, that engage in different levels of water contact at beaches at risk of blue-green algae blooms. The investigators will examine differences in illness risks by gender, age, and location. Relationships between cyanobacterial cell counts, toxin levels, and environmental conditions with the risk of acute illness among participants will be determined. Overall, results will provide important data on the risk of recreational water illness from exposure to blue-green algae and their toxins in Canadian beach settings.

Eligibility

Primary outcome measure(s)

• Incidence of gastrointestinal illness among participants — Within 3 days of beach visit
  Gastrointestinal illness is defined as one or more of: (a) diarrhea (≥3 loose stools in 24 hrs); (b) vomiting; (c) nausea with stomach cramps; or (d) nausea or stomach cramps that interfere with regular daily activities (e.g., missed work or school)

Trial sites (4)

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