Epidemiology of recreational exposure to freshwater cyanobacteria - an international prospective cohort study

Stewart, Ian, Webb, Penelope M., Schluter, Philip J., Fleming, Lora E., Burns, John W., Gantar, Miroslav, Backer, Lorraine C. and Shaw, Glen R. (2006) Epidemiology of recreational exposure to freshwater cyanobacteria - an international prospective cohort study. BMC Public Health, 6 93: 1-11. doi:10.1186/1471-2458-6-93

Author Stewart, Ian
Webb, Penelope M.
Schluter, Philip J.
Fleming, Lora E.
Burns, John W.
Gantar, Miroslav
Backer, Lorraine C.
Shaw, Glen R.
Title Epidemiology of recreational exposure to freshwater cyanobacteria - an international prospective cohort study
Journal name BMC Public Health   Check publisher's open access policy
ISSN 1471-2458
Publication date 2006-04-11
Sub-type Article (original research)
DOI 10.1186/1471-2458-6-93
Open Access Status DOI
Volume 6
Issue 93
Start page 1
End page 11
Total pages 11
Place of publication London, United Kingdom
Publisher Biomed Central
Collection year 2006
Language eng
Subject C1
321299 Public Health and Health Services not elsewhere classified
730299 Public health not elsewhere classified
Abstract Background: Case studies and anecdotal reports have documented a range of acute illnesses associated with exposure to cyanobacteria and their toxins in recreational waters. The epidemiological data to date are limited; we sought to improve on the design of some previously conducted studies in order to facilitate revision and refinement of guidelines for exposure to cyanobacteria in recreational waters. Methods: A prospective cohort study was conducted to investigate the incidence of acute symptoms in individuals exposed, through recreational activities, to low ( cell surface area < 2.4 mm(2)/mL), medium ( 2.4 - 12.0 mm(2)/mL) and high (> 12.0 mm(2)/mL) levels of cyanobacteria in lakes and rivers in southeast Queensland, the central coast area of New South Wales, and northeast and central Florida. Multivariable logistic regression analyses were employed; models adjusted for region, age, smoking, prior history of asthma, hay fever or skin disease ( eczema or dermatitis) and clustering by household. Results: Of individuals approached, 3,595 met the eligibility criteria, 3,193 (89%) agreed to participate and 1,331 (37%) completed both the questionnaire and follow-up interview. Respiratory symptoms were 2.1 (95% CI: 1.1 - 4.0) times more likely to be reported by subjects exposed to high levels of cyanobacteria than by those exposed to low levels. Similarly, when grouping all reported symptoms, individuals exposed to high levels of cyanobacteria were 1.7 ( 95% CI: 1.0 - 2.8) times more likely to report symptoms than their low-level cyanobacteria-exposed counterparts. Conclusion: A significant increase in reporting of minor self-limiting symptoms, particularly respiratory symptoms, was associated with exposure to higher levels of cyanobacteria of mixed genera. We suggest that exposure to cyanobacteria based on total cell surface area above 12 mm(2)/mL could result in increased incidence of symptoms. The potential for severe, life-threatening cyanobacteria-related illness is likely to be greater in recreational waters that have significant levels of cyanobacterial toxins, so future epidemiological investigations should be directed towards recreational exposure to cyanotoxins.
Keyword Public, Environmental & Occupational Health
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

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Created: Wed, 15 Aug 2007, 08:21:27 EST