Cryptosporidium and recreational water facilities


Of the numerous contaminates that may be present in recreational water the parasite cryptosporidium is one of the most resistant to common sanitation efforts. This microscopic organism is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very resistant to chlorine and other halogen-based disinfectants. The Center for Disease Control (CDC) chart below demonstrates how resistant the parasite can be even in properly treated water.

Disinfection Times for Fecal Contaminants in Chlorinated Water*

Contaminant Time
E. coli O157:H7 bacteria < 1 minute
Hepatitis A virus about 16 minutes
Giardia parasite about 45 minutes
Cryptosporidium parasite about 9,600 minutes (6.7 days)

* 1 ppm chlorine at pH 7.5 and 25 C

During the past two decades cryptosporidium, often called just crypto, has become recognized as one of the most common causes of waterborne disease within humans in our country. The parasite may be found in drinking water and recreational water in every region of the U.S. and throughout the world. According to the CDC the number of outbreaks of diarrhea connected with swimming pools is on the increase. As seen in the 2005 outbreak at Seneca Lake State Park in New York, thousands can become ill from a single outbreak. Crypto infections, though certainly not pleasant, are generally not serious. They may require hospitalization for higher risk groups such as pregnant women and young children, and can be life threatening for those with compromised or weakened immune systems. However, there have been very serious outbreaks that originated in drinking water systems – Milwaukee in 1993 with over 400,000 infected and 104 deaths; Las Vegas in 1994 with 100 infected and 19 deaths.

Every YMCA with recreational water, i.e., swimming pool, spa, water-park, or splash pad, runs the risk of harboring the parasite and hosting the next outbreak. Facilities that include features such as spray pools or splash pads may run a higher risk as guests may more easily inhale or ingest the airborne water particles. In addition children may spend more time in these facilities than they would in a traditional flat water or lap pool. These extended visits without sufficient bathroom breaks increase the risk of water contamination. Recent news casts have clearly and frequently demonstrated that hundreds and even thousands can become ill from this exposure. No YMCA wants its members or guests exposed to such an unpleasant and potentially harmful experience. Neither do any want to spend their limited existing resources for site closure and disinfection or to face a potential decline in their reputation and future resources that might result from the press’s depiction of them as a facility that allowed such unsafe and unsanitary conditions.

A Plan of Action

Much of the illness due to crypto, not surprisingly, is reported during the summer swim season when the numbers of swimmers, especially small children, increases. Many YMCAs operate indoor facilities year round, and as a result these sites must work to address the dangers of cryptosporidium all year long. Whether seasonal or continual, crypto poses a difficult problem for even the best-equipped and well-maintained aquatic centers. The following guidelines are intended to prevent a potential outbreak in your YMCA.

  1. Design: In optimal conditions, outbreaks of cryptosporidium and other recreational water illnesses can be addressed as early as the design stage of a new aquatic center. Pools that pose a greater risk for contamination, i.e. wading pools, kiddie pools, and therapy pools, should be designed with circulation and filtration systems separate from other pools. These systems should be maintained and operated to provide maximum filtration for each pool. It should be remembered that increased bather loads and environmental conditions may require a circulation system that exceeds the minimum requirement for the pool size. Also, the use of smaller filter media such as diatomaceous earth may be more effective at trapping crypto organisms.
  2. Management: The following steps can help to prevent and control an outbreak: a. Develop a policy for pool usage by diaper-aged and toddler children. Children in diapers or swim-diapers should only be permitted in designated pools such as the wading pool. Only parents or guardians should accompany the children in the wading pools and guests should rinse off in a shower before switching pools. Be aware that the use of swim diapers and swim pants may give many parents and staff a false sense of security regarding fecal contamination. No scientific data has been published that documents their effectiveness in preventing pool contamination by infection-causing germs or feces; it is unlikely that swim diapers are able to keep loose or diarrhea stools from leaking into the pool. b. Provide easily locatable and readily accessible diaper changing areas for parents to use; inspect and clean them frequently. c. Maintain proper sanitation levels according to your state or local codes, or at least 1.0 ppm residual chlorine. During high use or hot weather, free chlorine levels should be increased. Check chemical levels frequently and always obtain water samples from the pool or water feature itself, not from the circulation system. Remember to properly document all chemical readings. d. Locker room and toilet facilities should be disinfected daily. Pay particular attention to seats, floors, and decks. e. Develop a fecal accident plan f.Develop an emergency response plan to manage guests, the health department, and the media in the event of an outbreak. g. Establish and enforce rules regarding sanitary swim practices. h. In case of an outbreak, avoid the long pool closure that pools have historically done because of the outbreak. Rather, follow the Center for Disease Control’s recommendation of super-chlorinating the pool for at least 13 hrs using 20 ppm chlorine at a pH of 7.5 (not effective if cyanurates are used as a chlorine stabilizer) and then re-opening as soon as possible. The reason for this is that if the pool is closed for an extended period of time, the sick swimmers will continue to swim, but in other pools, thereby spreading the organism further.
  3. Rules: The following rules are designed to keep your pool safe and sanitary. Most are required by state and local codes. Rules are only effective if they are strictly and consistently enforced. a. Children who are not toilet trained should wear swim-diapers or swim-pants and should be restricted to the wading or kiddie pool if possible. The swim-diapers should fit snugly enough at waist and legs and be of ample size so that any fecal activity will be fully contained. Inadequately attired children should not be allowed entry. b. Persons with bandages or open wounds or those known to have or who are visibly affected by infection or illness should not use the pool. This is extremely important with regard to any illness involving diarrhea or loose stools as swim diapers are incapable of completely containing such excrement. c. Diapers may not be changed at the poolside. d. All patrons must take a soap shower. e. Street shoes should not be worn on the pool deck or in any water attraction.
  4. Education: Use the YMCA newsletter, program, flyers, signage, or any other effective means of communication to educate your members on the risk of cryptosporidium and other recreational water borne illnesses. Explain the efforts that the YMCA has taken to keep the members safe; also provide information on how members can best protect themselves. The following are appropriate rules. a. Users must read and follow all posted rules and must follow lifeguard and staff instructions when requested. b. Do not use the pool if you or your child has had diarrhea in the previous 2 weeks. (This should be stressed at the beginning of every class or program involving non-toilet trained children.) c. Assist young children in making frequent visits to the bathroom to minimize accidents. d. Pool water is not intended for rinsing. Do not rinse children in the pool before, during, or after diaper changes. Do not rinse hands in the pool after a trip to the bathroom or after changing a child's diaper. Always wash hands correctly by using soap and warm water. e. Notify the management if you or a family member develops a gastrointestinal illness that you think may have been related to a visit to the swimming pool.
  5. Spray Parks: Many public, private, and semi-private aquatic facilities in the past few years have installed zero-depth water features such as splash pads and interactive spray parks. These features have obvious benefits…they are fun, which increases membership, and there is much less chance of drowning. Unfortunately, these features also have significant drawbacks that often are inadequately considered before installation. These issues include the cost of water, recirculation and sanitation systems, water runoff issues, and disease transmission. That many jurisdictions’ bathing codes inadequately address sanitation issues in spray parks was clearly demonstrated at New York’s Seneca Lake State Park where over 5,000 visitors got sick, the worst of several such outbreaks in the summer of 2005 and the third largest outbreak in the U.S. in the last decade. This will change eventually, prompted by this and similar outbreaks, but until that time the operators of these attractions must take the necessary steps to prevent disease transmission.

A spray park, splash pad, or similar feature should be treated in the same manner as any other pool in the terms of disease transmission. Water quality should be held to the same sanitation standards as swimming pool water and should be check regularly. In addition to the rules above, guests utilizing the attraction should be dressed appropriately for swimming and should not be wearing street shoes.

As is the case with a swimming pool, a spray park offers fun for guests and benefits to your facility but is not without inherent risk. A spray park requires just as much attention and management as a swimming pool to ensure that the patrons enjoy a safe and sanitary experience at your facility. More facilities, including many YMCAs will consider these attractions in the near future, and it is important that the requirements for operation are fully understood in advance.

Adhering to the above guidelines will help you keep your YMCA aquatic facilities as safe and sanitary as possible for your guests. Constant attention may prevent your YMCA from becoming the origin of the next outbreak of cryptosporidium or of a more dangerous organism.

Please call us at 800-463-8546 to discuss this or any other risk management safety tip, or visit our web site at to learn more about YMCA risk management issues.


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