Outbreaks associated with recreational water in the United States

Abstract

In this article, we review the causes of outbreaks associated with recreational water during 1971 – 2000. A bacterial or protozoan etiology was identified in three-quarters of the outbreaks; 23% of the outbreaks were of undetermined etiology. The most frequently identified agents were Cryptosporidium (15%), Pseudomonas (14%), Shigella (13%), Naegleria (11%), Giardia (6%), and toxigenic E. coli (6%). Outbreaks attributed to Shigella, E. coli O157:H7, and Naegleria were primarily associated with swimming in fresh waters such as lakes, ponds, and rivers. In contrast, outbreaks caused by Cryptosporidium and Giardia were primarily associated with treated water in swimming and wading pools. Important sources of contamination for both treated and untreated recreational waters were the bathers themselves. Contamination from sewage discharges and wild or domestic animals were also important sources for untreated waters. Contributing factors in swimming-pool outbreaks were inadequate attention to maintenance, operation, disinfection, and filtration. Although not all waterborne outbreaks are recognized nor reported, the national surveillance of these outbreaks has helped identify important sources of contamination of recreational waters and the etiologic agents. This information can affect prevention recommendations and research priorities that may lead to improved water quality guidelines.

Keywords:

• Waterborne disease
• waterborne pathogens
• swimming and bathing
• water quality

Acknowledgments

We wish to acknowledge the efforts of the epidemiologists, microbiologists, engineers, sanitarians, and other health officials who have investigated and reported the outbreaks and our colleagues at the CDC with whom we have collaborated during the past thirty years, especially Deborah Levy, Michael Beach, Barbara Herwaldt, Sherline Lee, and Jonathan Yoder. Without their cooperation, this summary would not be possible.

Notes

* & Associates

Additional information

Notes on contributors

Michael F Craun

* & Associates