CDC at Work: Healthy Swimming
The Healthy Swimming Program works to protect the health of swimmers and aquatics staff by:
- Studying recreational water illnesses (RWIs) and how to prevent the spread of the germs that cause them
- Studying pool chemical–associated health events and how to prevent them
- Communicating study results to the public, state and local public health colleagues, aquatics staff, and lawmakers
Research and Communications
- Studying RWIs to learn who they impact and when and where they occur in the United States. Recent areas of focus include:
- Developing resources and recommendations for preventing RWIs and controlling RWI outbreaks and making these resources and recommendations readily available on the Healthy Swimming website.
- Promoting healthy swimming during Healthy and Safe Swimming Week (the week before Memorial Day) and throughout the year.
- Conducting laboratory and field research to explore recreational water treatment options for reducing the number of RWI outbreaks associated with chlorine-tolerant microbes, most notably Cryptosporidium (or Crypto for short). Projects include:
- Laboratory studies to determine the effectiveness of high levels of chlorine (i.e, “hyperchlorinaton”) to kill Crypto. Results of these studies provided information on the concentration of chlorine and time required to kill 99.9% of Crypto.
- Laboratory studies to determine the effect of both low and high levels of cyanuric acid (an additive commonly used to stabilize chlorine in pools) on killing Crypto under hyperchlorination conditions. Results of these studies will provide information on the concentration of chorine and time required to kill 99.9% of Crypto when cyanuric acid is present.
- Laboratory studies to determine the effectiveness of chlorine dioxide for killing Crypto. Results of these studies will provide information on the concentration of chlorine dioxide (both alone and in the presence of the standard level of chlorine in pools) and time required to kill 99.9% of Crypto.
- Field studies to examine how effective filters are in removing Crypto from the water under typical swimming pool conditions with and without coagulants, which are chemicals used increase the ability of filters to remove particles from the water.
- Field and molecular-based laboratory studies to determine how often pools are contaminated with Crypto and other common waterborne pathogens by examining samples taken from pool filters.
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