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Rapidly measured indicators of recreational water quality andswimming-associated illness at marine beaches: a prospective cohort study
Citation:
WADE, T. J., E. A. SAMS, K. P. BRENNER, R. A. HAUGLAND, E. C. CHERN, M. Beach, L. J. WYMER, C. C. RANKIN, D. Love, Q. Li, R. Noble, AND A. P. DUFOUR. Rapidly measured indicators of recreational water quality andswimming-associated illness at marine beaches: a prospective cohort study. ENVIRONMENTAL HEALTH. Academic Press Incorporated, Orlando, FL, 9(1):66, (2010).
Impact/Purpose:
To field test and validate new and faster approaches to measuring recreational water quality using a molecular method and to develop associations between these methods and illnesses among swimmers.
Description:
Background: In the United States and elsewhere, recreational water is monitored for fecal indicator bacteria to prevent illness. Standard methods to measure fecal indicator bacteria take at least 24 hours to obtain results. Molecular approaches such as quantitative polymerase chain reaction (qPCR) can estimate these bacteria faster, in under 3 hours. Previously, we demonstrated that measurements of the fecal indicator bacteria Enterococcus using qPCR, was associated with gastrointestinal (GI) illness at freshwater beaches. In this paper, we report on results from three additional marine beach sites. Methods: We interviewed beach-goers and collected water samples at marine beaches affected by treated sewage discharges in Mississippi in 2005, and Rhode Island and Alabama in 2007. Ten to twelve days later, we obtained information about gastrointestinal, respiratory, eye, ear and skin symptoms by telephone. We tested water samples for fecal indicator organisms using qPCR and other methods. Results: We enrolled 6,350 beach-goers. The risk of GI illness among swimmers was associated with a logjs-increase in exposure to qPCR-determined estimates of fecal indicator organisms in the genus Enterococcus (AOR=2.6, 95% CI 1.3-5.1) and Bacteroidales (AOR=1.9, 95% CI 1.3-2.9). Estimates of organisms related to Clostridium perfringens and a subgroup of organisms in the genus Bacteroides were also determined by qPCR in 2007, as was F+ coliphage, but relationships between these indicators and illness were not statistically significant. Conclusions: GI illnesses among swimmers were associated with the fecal indicator organisms Enterococcus and Bacteroidales estimated by qPCR at marine beaches affected by treated sewage discharges. This document is an internal draft for review purposes only. It has not been subjected to peer and administrative review and does not constitute US Environmental Protection Agency (EPA) policy. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy. Mention of trade names or commercial products does not constitute endorsement or recommendationfor use. The findings and conclusions in this report are those of the authors and do not represent the views of the Centers for Disease Control and Prevention or the EPA.
