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

Ian Stewart, Penelope M. Webb, Philip J. Schluter, Lora E. Fleming, John W. Burns, Miroslav Gantar, Lorraine C. Backer, Glen R. Shaw

Research output: Contribution to journalArticle

48 Citations (Scopus)

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 mm2/mL), medium (2.4-12.0 mm2/mL) and high (>12.0 mm2/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 mm2/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.

Original languageEnglish
Article number93
JournalBMC Public Health
Volume6
DOIs
StatePublished - Apr 11 2006
Externally publishedYes

Fingerprint

Cyanobacteria
Fresh Water
Epidemiology
Cohort Studies
Prospective Studies
Water
New South Wales
Queensland
Seasonal Allergic Rhinitis
Eczema
Incidence
Dermatitis
Lakes
Skin Diseases
Rivers
Cluster Analysis
Asthma
Logistic Models
Smoking
Regression Analysis

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

Cite this

Stewart, I., Webb, P. M., Schluter, P. J., Fleming, L. E., Burns, J. W., Gantar, M., ... Shaw, G. R. (2006). Epidemiology of recreational exposure to freshwater cyanobacteria - An international prospective cohort study. BMC Public Health, 6, [93]. https://doi.org/10.1186/1471-2458-6-93

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.; Shaw, Glen R.

In: BMC Public Health, Vol. 6, 93, 11.04.2006.

Research output: Contribution to journalArticle

Stewart, I, Webb, PM, Schluter, PJ, Fleming, LE, Burns, JW, Gantar, M, Backer, LC & Shaw, GR 2006, 'Epidemiology of recreational exposure to freshwater cyanobacteria - An international prospective cohort study', BMC Public Health, vol. 6, 93. https://doi.org/10.1186/1471-2458-6-93
Stewart, Ian ; Webb, Penelope M. ; Schluter, Philip J. ; Fleming, Lora E. ; Burns, John W. ; Gantar, Miroslav ; Backer, Lorraine C. ; Shaw, Glen R. / Epidemiology of recreational exposure to freshwater cyanobacteria - An international prospective cohort study. In: BMC Public Health. 2006 ; Vol. 6.
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