A pool may be a good place to cool off and relax on a hot summer day, but even one that looks clean could be swimming in microscopic parasites.
The most common culprit when it comes to swimming-related illness — particularly in public pools or water parks — is cryptosporidium, or crypto for short. It’s spread through fecal matter, and even a small amount can contain millions of germs.
Regular levels of chlorine won’t kill crypto, which can survive in a well-maintained pool for up to 10 days. It’s also easy to catch.
The Centers for Disease Control and Prevention says that swallowing even one mouthful of water infected with crypto can lead to weeks of diarrhea, nausea, and vomiting.
Consumer Reports health editors say parents should instruct children on the importance of not swallowing pool water and to take frequent bathroom breaks to reduce accidents. That includes children who wear swim diapers because they are not foolproof.
Editors also say anyone who is experiencing diarrhea or has been sick in other ways should not swim. People should also take a shower or at least rinse off before they swim.
If fecal matter does get into the pool, don’t take any chances.
Consumer Reports says shut it down and get everyone out of the water.
The only way to effectively kill crypto is to have a professional super-chlorinate the water and then slowly bring it back to normal levels again, a process that can take at least eight hours.
If you get sick after swimming, your doctor can run tests to see whether crypto is the cause. If it is, the CDC says you should wait a full two weeks after the diarrhea has stopped before you get back in a pool.