Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content

Medical Professionals

Doctor with mom and child The number of recreational water illness (RWI) outbreaks reported annually has increased dramatically in recent years. Cryptosporidium, which can stay alive for days even in well-maintained pools, has become the leading cause of swimming pool-related outbreaks of diarrheal illness. In 2011 and 2012, public health officials from 32 states and Puerto Rico reported 90 recreational water–associated outbreaks. Among the outbreaks caused by infectious pathogens, 37 (54%) were caused by Cryptosporidium 1.

Studies show that the swimming public believes that chlorine instantly kills all pathogens. These data also show that swimmers don’t think about swimming as a shared water experience. Unfortunately, these misconceptions lead to risky behaviors, such as swimming during diarrheal illness and swallowing recreational water, which lead to transmission of pathogens that cause RWIs. It is important for medical professionals to educate their patients and dispel misconceptions that lead to illness 2.

5 Prevention Messages

Here are 5 simple prevention messages medical professionals can share with their patients to help them proactively protect their health and the health of others every time they swim.

  • Don’t swim while ill with diarrhea.
  • For patients with cryptosporidiosis, don’t swim for an additional 2 weeks after diarrhea has resolved.
  • Don’t swallow the water.
  • Keep ears as dry as possible and dry ears thoroughly after swimming.
  • Don’t swim when you have open wounds.

Infection Control

Infection control practitioners need to know the recommendations for hydrotherapy tanks developed by the CDC and the Healthcare Infection Control Practices Advisory Committee (HICPAC).

The following resources are also available within the CDC Healthy Swimming website:

For diagnostic assistance on parasitic diseases, laboratorians may consult with CDC’s Division of Parasitic Diseases through DPDx.


  1. Hlavsa MC, Roberts VA, Kahler AM, Hilborn ED, Mecher TR, Beach MJ, Wade TJ, Yoder, JS. Outbreaks of illness associated with recreational water — United States, 2011–2012. MMWR Morb Mortal Wkly Rep. 2015;64(24):668-672.
  2. Castor ML, Beach MJ. Reducing illness transmission from disinfected recreational water venues: Swimming, diarrhea, and the emergence of a new public health concern. Pediatr Infect Dis J. 2004;23(9):866-70.