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

NCT06579170 | Active Not Recruiting

• 1 other identifier: 2324-HQ-000024
• Study Type: observational
• Target: 2,500
• Locations: 1 country
• Sites: 4

Brief 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.

Conditions

Gastroenteritis; Gastrointestinal Diseases; Eye Infections; Skin Infections; Respiratory Tract Infections; Blue Green Algae Poisoning

Keywords

Cohort study; Harmful algal blooms; Recreational water contact; Cyanobacteria; One Health

Outcome Measures

Primary Outcomes (1)

• Incidence of gastrointestinal illness among participants

  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)

  Within 3 days of beach visit

Secondary Outcomes (4)

• Incidence of respiratory illness among participants

  Within 3 days of beach visit

• Incidence of eye infections among participants

  Within 3 days of beach visit

• Incidence of skin infections among participants

  Within 3 days of beach visit

• Incidence of generalized symptoms among participants

  Within 3 days of beach visit

Other Outcomes (1)

• Incidence of illness severity measures among participants

  Within 3 days of beach visit

Study Arms (1)

Recreational water users

Recreational water users of any age and their pet dogs present at the beaches and waterfronts in this study during recruitment days.

Behavioral: Cyanobacteria exposure during water contact

Interventions

Cyanobacteria exposure during water contact BEHAVIORAL

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

Recreational water users

Eligibility Criteria

• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Recreational water users of any age, and any pet dogs also present at the beaches/waterfront areas, during the study recruitment days.

You may qualify if:

• ability to provide informed consent
• ability to complete the surveys in English or French
• must not have participated in the study in the past 21 days

Sponsors & Collaborators

• Toronto Metropolitan University: lead
• Ontario Ministry of the Environment, Conservation and Parks: collaborator
• Manitoba Environment and Climate Change: collaborator
• Windsor-Essex County Health Unit: collaborator
• Canadian Veterinary Medical Association: collaborator
• Health Canada: collaborator

Study Sites (4)

Grand Beach

Winnipeg, Manitoba, R0E 0T0, Canada

Location

Shubenacadie Canal

Halifax, Nova Scotia, B2X 2W5, Canada

Location

Kinsmen beach

Port Perry, Ontario, L9L 1R2, Canada

Location

Colchester Beach

Windsor, Ontario, N0R 1G0, Canada

Location

Related Publications (1)

• Young I, Sanchez JJ, Sekerciouglu F, Desta BN, Holeton C, Lyng D, Peczulis V, Renwick S, Brooks T, Tustin J. Burden of recreational water illness due to exposure to cyanobacteria and their toxins in freshwater beaches in Canada: protocol of a prospective cohort study. BMJ Open. 2024 Jun 12;14(6):e085406. doi: 10.1136/bmjopen-2024-085406.

  PMID: 38866574 BACKGROUND

MeSH Terms

Conditions

Gastroenteritis; Gastrointestinal Diseases; Eye Infections; Cellulitis; Respiratory Tract Infections

Condition Hierarchy (Ancestors)

Digestive System Diseases; Infections; Eye Diseases; Skin Diseases, Infectious; Suppuration; Connective Tissue Diseases; Skin and Connective Tissue Diseases; Inflammation; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Respiratory Tract Diseases

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: August 28, 2024
• First Posted: August 30, 2024
• Study Start: June 1, 2024
• Primary Completion: September 15, 2025
• Study Completion: March 31, 2026
• Last Updated: September 9, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE
• Time Frame: Study protocol is already published. Code and dataset will be shared after study publication of results.

Locations

CA (4)