GastroenteritisNCT06579170
Burden of Recreational Water Illness Due to Exposure to Cyanobacteria and Their Toxins in Freshwater Beaches in Canada
An observational study of Gastroenteritis and Gastrointestinal Diseases, run by Toronto Metropolitan University at 4 sites in Canada.
Trial 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. Read more about this study
- Who is it for?
- Any ageHealthy volunteers can take part
- Conditions the study is for
- Gastroenteritis, Gastrointestinal Diseases, Eye Infections
- What is being tested?
- Cyanobacteria exposure during water contact
- Type of treatment
- Lifestyle or therapy programme
- How many people
- 2,500 participants
- Where
- 4 sitesCanada
- Study dates
- 1 Jun 2024to 31 Mar 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
Study population: Recreational water users of any age, and any pet dogs also present at the beaches/waterfront areas, during the study recruitment days.
Who may be able to join
- 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
Who cannot join
None listed.
Trial locations and contacts
4 sites in 1 country.
Canada4 sites
Shubenacadie Canal
Halifax, Nova Scotia, B2X 2W5
Kinsmen beach
Port Perry, Ontario, L9L 1R2
Colchester Beach
Windsor, Ontario, N0R 1G0
Grand Beach
Winnipeg, Manitoba, R0E 0T0
About this study
Official title: Burden of Recreational Water Illness Due to Exposure to Cyanobacteria and Their Toxins in Freshwater Beaches in Canada: a Prospective Cohort Study
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.
Read the 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.
- Conditions
- Gastroenteritis, Gastrointestinal Diseases, Eye Infections, Skin Infections, Respiratory Tract Infections, Blue Green Algae Poisoning
- Being tested
- Cyanobacteria exposure during water contact
- Keywords
- Cohort study, Harmful algal blooms, Recreational water contact, Cyanobacteria, One Health
- Medical subject headings
- Gastroenteritis, Gastrointestinal Diseases, Eye Infections, Cellulitis, Respiratory Tract Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Cyanobacteria exposure during water contactBehavioural
Cyanobacteria levels in beach water among participants who report water contact in the beach survey
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: Behavioral: Cyanobacteria exposure during water contact |
What is being measured
The primary outcome is the main question the study is designed to answer.
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)
Measured: Within 3 days of beach visit
Secondary outcomes (4)
Incidence of respiratory illness among participants
Defined as: sore throat, runny or congested nose, difficulty breathing, or cough
Measured: Within 3 days of beach visit
Incidence of eye infections among participants
Defined as: eye infection or irritation
Measured: Within 3 days of beach visit
Incidence of skin infections among participants
Defined as: rash or itchy skin
Measured: Within 3 days of beach visit
Incidence of generalized symptoms among participants
Defined as: headache, fever, fatigue, dizziness, loss of appetite, chills, muscle pain, or general pain
Measured: Within 3 days of beach visit
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Aug 2024
- Study start1 Jun 2024
- Primary completion15 Sep 2025 (estimated)
- Study completion31 Mar 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for GastroenteritisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 2,500 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Toronto Metropolitan University
- Sponsor type
- University, hospital or other
- Collaborators
- Ontario Ministry of the Environment, Conservation and Parks, Manitoba Environment and Climate Change, Windsor-Essex County Health Unit, Canadian Veterinary Medical Association, Health Canada
- Responsible party
- Principal investigator, Ian Young, Toronto Metropolitan University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06579170
- Sponsor's protocol ID
- 2324-HQ-000024
- Status last verified
- Sep 2025
- First submitted
- 28 Aug 2024
- Last updated
- 9 Sep 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: An anonymized dataset will be shared publicly after results are published.
Publications
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.
PubMed 38866574
Study at a glance
From the registry record, last updated by the sponsor on 9 Sep 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Burden of Recreational Water Illness Due to Exposure to Cyanobacteria and Their Toxins in Freshwater Beaches in Canada: a Prospective Cohort Study
- ClinicalTrials.gov ID
- NCT06579170
- Acronym / sponsor ID
- 2324-HQ-000024
- 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
- Study type
- Observational
- Recruitment status
- Active, not recruiting
- Enrolment
- 2,500 participants (estimated)
- Lead sponsor
- Toronto Metropolitan UniversityUniversity, hospital or other
- Collaborators
- Ontario Ministry of the Environment, Conservation and Parks, Manitoba Environment and Climate Change, Windsor-Essex County Health Unit, Canadian Veterinary Medical Association, Health Canada
- Study start
- 1 Jun 2024 (actual)
- Primary completion
- 15 Sep 2025 (estimated)
- Study completion
- 31 Mar 2026 (estimated)
- First posted
- 30 Aug 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Recreational water users | – | Behavioral: Cyanobacteria exposure during water contactRecreational water users of any age and their pet dogs present at the beaches and waterfronts in this study during recruitment days. |
Who may qualify
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Recreational water users of any age, and any pet dogs also present at the beaches/waterfront areas, during the study recruitment days.
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Cyanobacteria exposure during water contactCyanobacteria levels in beach water among participants who report water contact in the beach survey | Behavioural | Recreational water users |
Primary outcome
Incidence of gastrointestinal illness among participants
Time frame: 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)
4 secondary outcomes
Incidence of respiratory illness among participants
Time frame: Within 3 days of beach visit
Incidence of eye infections among participants
Time frame: Within 3 days of beach visit
Incidence of skin infections among participants
Time frame: Within 3 days of beach visit
Incidence of generalized symptoms among participants
Time frame: Within 3 days of beach visit
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Sep 2025.
- Background: PubMed 38866574Young 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.
- Individual participant dataSharing planned: Yes. An anonymized dataset will be shared publicly after results are published.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
4 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Gastroenteritis and Gastrointestinal Diseases, run by Toronto Metropolitan University at 4 sites in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 9 Sep 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 4 sites in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of gastrointestinal illness among participants (time frame: Within 3 days of beach visit). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06579170, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Sep 2025.