Colorado State University Extension
SafeFood Rapid Response Network
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AVOIDING RWIS WHILE SWIMMING
Edited by: Marissa Bunning, Ph.D., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Spring 2007
With spring and summer months and an increase in outdoor activities right around the corner, it is time to start thinking about swimming safety issues. Most people think first of concerns over children drowning in neighborhood pools or lakes, but there are also risks of illness from swimming in public areas. Illnesses caused by E. coli and other pathogens are often associated with foods such as undercooked meats and raw vegetables, but can also be spread by ingesting water that is contaminated with them. Illnesses caused by pathogen transmission in swimming pools are often referred to as recreational water illnesses, or RWIs, and become a concern especially for children and families who swim in public pools or lakes in the summer.
The Centers for Disease Control and Prevention (CDC) defines RWIs as illnesses spread by swallowing, breathing, or contacting contaminated water in swimming pools, hot tubs, lakes, rivers, or oceans. These illnesses can cause diarrheal, respiratory, skin, ear, and neurologic infections, although the most commonly reported RWI symptom is diarrhea. Since 1978, the CDC has collected information on RWI outbreaks in the United States. The most common causes of RWI outbreaks are Cryptosporidium, E. coli, Giardia, Shigella, and Norovirus, pathogens usually linked to contaminated foods.
The CDC has found that most outbreaks of diarrhea associated with swimming pools and lakes occur during the summer months, and that cases have increased since 1985. The 10 or so diarrheal illness outbreaks linked to public swimming pools each year are thought to be just the tip of the iceberg. Among the pathogens of concern, E. coli is sensitive to chlorine, and thus more often causes illness in lakes or other swimming areas where chlorine is not added. Cryptosporidium, however, is resistant to chlorine and can survive in chlorinated swimming pools. When young children in diapers, especially those with diarrheal illness, swim in public areas, these pathogens can contaminate the water and spread to others who accidentally swallow swimming water.
As part of the ongoing research about RWIs, the CDC has interviewed parents about the safety risks of swimming, and has found that most are not aware that swimming can cause illness through ingestion of contaminated water. Many parents indicated that they believe a pool is safe and clean when they smell chlorine at around the pool area. Some pathogens, however, can live for hours or even days in chlorinated pools, even those that are well-maintained. Because swimming is a very popular warm-weather activity especially for children, parents indicated in the interviews that they would like to have better education and more information about RWIs and how they are spread.
The CDC has responded by providing detailed information about swimming risks and illness prevention, targeted towards the general public and available at the CDC website. These recommendations to promote healthy swimming are outlined as "PLEAs" for both swimmers and parents of young children.
The "PLEAs" for swimmers are:
- Please don't swim when you have diarrhea.
- Please don't swallow the pool water, and avoid getting water in your mouth.
- Please practice good hygiene.
The three "PLEAs" for parents are:
- Please take your kids on bathroom breaks or check diapers often.
- Please change diapers in a bathroom and not at poolside.
- Please wash your child thoroughly with soap and water before swimming.
The CDC encourages parents to use these guidelines and to consider RWIs as much a part of safe swimming education as the prevention of drowning and swimming-related injuries. RWI illness prevention becomes most important now, as the summer months and swimming weather draw near.
Sources:
- U.S. Centers for Disease Control and Prevention. Healthy Swimming. June 2006. Available at: www.cdc.gov/healthyswimming/6_pleas.htm.
- U.S. Centers for Disease Control and Prevention. Questions and Answers for Aquatics Staff. May 2003. Available at: www.cdc.gov/healthyswimming/faq/operators_print.htm.
- U.S. Centers for Disease Control and Prevention. What are RWIs. July 2006. Available at: www.cdc.gov/healthyswimming/what.htm.
