Warning issued on cryptosporidium, fecal parasite that can live up to 7 days in swimming pools.

Published: July 4, 2019 | Updated: July 30, 2020

It’s finally summer. With the warm temperatures here to stay, many families are heading to swimming pools. Before you jump in, the Centers for Disease Control and Prevention (CDC) has a warning: Pools can carry many waterborne diseases, including cryptosporidiosis, an illness caused by ingesting cryptosporidium, a fecal parasite.

In fact, the CDC reports that during 2009–2017, 444 cryptosporidiosis outbreaks, resulting in 7,465 cases, were reported by 40 states and Puerto Rico. Recreational water — mostly swimming pools, but also kiddie pools and water playgrounds — were responsible for 156 outbreaks, more than a third of the cases. Untreated water (such as lakes) and drinking water caused 22 more cases.

What is cryptosporidium and cryptosporidiosis?

The microscopic germ cryptosporidium, also called crypto, is a fecal parasite that causes cryptosporidiosis, a disease that causes watery diarrhea. Pools can be at more of a risk because an infected swimmer can excrete the parasite at levels several orders of magnitude higher than the amount necessary to cause infection.

Cryptosporidiosis can affect all people, but some groups are likely to become sicker due to crypto. Young children, pregnant women and people with weakened immune systems are at risk for severe illness related to ingesting crypto. Crypto has a high tolerance to chlorine — it can survive in a properly chlorinated pool for up to seven days, according to the CDC.

“If your child isn’t feeling well, he or she should stay out of the pool,” said Mark A. Brockman Jr., M.D., pediatrician with Norton Children’s Medical Group – Iroquois. “Your child could pass on an illness to others, since chlorine may not be as effective against some parasites and organisms.”

How to stay safe from waterborne illness this summer

The CDC offers these tips to keep from getting sick from pools, water parks and lakes:

• Don’t swim or let kids swim if sick, especially with diarrhea.
• Check pool, hot tub and water playground inspection scores.
• Before getting in the water, use a test strip from your local retailer or pool supply store to check if the water’s pH and bromine or free chlorine level are correct.
• Don’t swallow the water.
• Take kids on bathroom breaks hourly and change diapers away from the water. Make sure children wash their hands after going to the bathroom and before getting back into the water.