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

T

Toronto Metropolitan University

Status

Active, not recruiting

Conditions

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

Treatments

Behavioral: Cyanobacteria exposure during water contact

Study type

Observational

Funder types

Other

Identifiers

NCT06579170
2324-HQ-000024

Details and patient eligibility

About

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.

Full description

This study will investigate the incidence of recreational water illness due to exposure to cyanobacterial blooms and their toxins in four targeted and popular freshwater beaches in Ontario, Manitoba, and Nova Scotia, Canada. A prospective cohort design and One Health approach will be used. On-site recruitment of recreational water users will be conducted at two beaches per year during the summers of 2024 and 2025. The population of interest includes recreational water users of any age and their pet dogs. After enrollment, an in-person survey will determine beach exposures and confounding factors, and a three-day follow-up survey will ascertain any acute illness outcomes experienced by participants or their dogs. The target sample size is 2500 recreational water users. Water samples will be taken each recruitment day and analyzed for cyanobacterial indicators (pigments), cell counts, and toxin levels. Regression analysis will be conducted to estimate the association with water contact, cyanobacterial levels, and risks of different acute illness outcomes.

Enrollment

2,500 estimated patients

Sex

All

Volunteers

Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria:

  • 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

Trial design

2,500 participants in 1 patient group

Recreational water users
Description:
Recreational water users of any age and their pet dogs present at the beaches and waterfronts in this study during recruitment days.
Treatment:
Behavioral: Cyanobacteria exposure during water contact

Trial contacts and locations

4

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Data sourced from clinicaltrials.gov

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