Clinical trial NCT06579170: Burden of Recreational Water Illness Due to Exposure to Cyanobacteria and Their Toxins in Freshwater Beaches in Canada
Official title: Burden of Recreational Water Illness Due to Exposure to Cyanobacteria and Their Toxins in Freshwater Beaches in Canada: a Prospective Cohort Study
Study type: OBSERVATIONAL
Overall status: ENROLLING_BY_INVITATION
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
Lead sponsor: Toronto Metropolitan University
Sponsor class: OTHER
Collaborators: name: Ontario Ministry of the Environment, Conservation and Parks
name: Manitoba Environment and Climate Change
name: Windsor-Essex County Health Unit
name: Canadian Veterinary Medical Association
name: Health Canada
First posted: 2024-08-30
Enrollment: 2500
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
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.

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.

Detailed 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.

Eligibility 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

Primary outcomes:
measure: Incidence of gastrointestinal illness among participants
timeFrame: Within 3 days of beach visit
Secondary outcomes:
measure: Incidence of respiratory illness among participants
timeFrame: Within 3 days of beach visit
measure: Incidence of eye infections among participants
timeFrame: Within 3 days of beach visit
measure: Incidence of skin infections among participants
timeFrame: Within 3 days of beach visit
measure: Incidence of generalized symptoms among participants
timeFrame: Within 3 days of beach visit
Other outcomes:
measure: Incidence of illness severity measures among participants
timeFrame: Within 3 days of beach visit
Locations:
city: Winnipeg
country: Canada
facility: Grand Beach
state: Manitoba
city: Halifax
country: Canada
facility: Shubenacadie Canal
state: Nova Scotia
city: Port Perry
country: Canada
facility: Kinsmen beach
state: Ontario
city: Windsor
country: Canada
facility: Colchester Beach
state: Ontario
Study officials:
References:
citation: 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.