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Ready for summer swimming? Beware of hidden harms


While cooling off in a pool or lake may look refreshing on a hot summer’s day, you may want to be aware of this danger lurking beneath the surface before taking the plunge. 

It’s as gross as it sounds, Cryptosporidium is a parasite that can be found in water sources including chlorinated water such as swimming pools. The parasite is usually transmitted person to person through the fecal-oral route. If someone gets infected and has this parasite in their stool and the stool gets into a water system or onto an object that gets into the mouth of another person, then that would cause transmission. 

In 2016, at least 32 Cryptosporidium outbreaks were reported in pools or water playground in the U.S., compared with 16 outbreaks in 2014, according to a recent report from the Centers for Disease Control and Prevention.

According to Maggie Hagan, MD, infectious disease specialist at Via Christi, part of Ascension, the largest nonprofit health system in the U.S. and the world’s largest Catholic health system, the main symptom associated with Cryptosporidium is a watery diarrhea which in most people, if they are otherwise healthy, is going to be self-limited. 

“They might feel bad for a couple of weeks, but it will go away on its own,” said Dr. Hagan. “No specific treatment is needed for patients who don't have a weakened immune system, but patients who are immunocompromized may require treatment. Any time someone has diarrhea we want to keep them from getting dehydrated which can sometimes happen since this is an infection which typically happens during the hot summer months. If someone did develop this disease, it would be important to drink lots of fluids. They also can take anti-diarrheal medication.”

Ways to avoid Cryptosporidium:

  • Avoid swimming in a pool that has obvious fecal contamination.
  • Parents of young children should check the child’s diaper every hour or so to make sure they haven’t had a bowel movement.
  • Make sure young children aren’t swallowing the water in the swimming pool or lake, as this is the likely route of transmission of Cryptosporidium.
  • Don’t have beverages in a swimming pool or water source. Contaminated water can splash into the drink or the container.
  • Wash items soiled with feces or vomit as soon as possible. 

The best way to avoid spreading Cryptosporidium is to have good hand hygiene. Wash your hands with soap and water often. Alcohol-based sanitizers don’t work against Cryptosporidium.