swimming bug

Watch Out for This Unpleasant Swimming Pool ‘Bug’

What would summer be without the silky feel of warm water caressing hot skin as you glide across a swimming pool?

But as a timely reminder that nothing is perfect, this month the U.S. Centers for Disease Control and Prevention (CDC) in Atlanta published a report warning swimmers to take precautions against a microscopic parasite that can take up residence in pools and water playgrounds. So our concierge family practice doctors at MD 2.0 in Jupiter want to alert you to this possible hazard.

Symptoms and Causes

The infection, Cryptosporidium, or “Crypto,” is the most common cause of diarrhea and occurs when swimmers swallow pool water which is infected with it. The resulting illness can last for up to three weeks, leaving sufferers with watery diarrhea, stomach cramps, nausea or vomiting, and, possibly, dehydration as a result.

The CDC’s June report noted that, between 2009-2017, reported outbreaks have increased an average of 13 percent per year. Thirty-five percent of the outbreaks were linked to swimming in pools and water playgrounds; 15 percent were linked to contact with cattle, particularly nursing calves; 13 percent were linked to contact with infected people in childcare settings; and three percent were linked to drinking raw (i.e., unpasteurized) milk or apple cider.

Tough to Kill

Unlike other swimming pool infections, Crypto is resistant to the typical concentration of chlorine. Crypto is protected by an outer shell that makes it tough to kill, the CDC reports. For example, it can survive for days in chlorinated water in pools and water playgrounds or on surfaces disinfected with chlorine bleach.

Crypto can easily cause outbreaks because it only takes a few germs to make someone sick, and there can be millions of Crypto germs in feces.

Even in pools which are treated to recommended levels, the Crypto parasite can survive for up to 10 days. The only way to respond to an outbreak of Crypto, the CDC says, is closing the pool and treating the water with high levels of chlorine, called hyperchlorination.

“Young children can get seriously sick and easily spread Crypto,” said Michele Hlavsa, R.N., M.P.H., chief of the CDC’s Healthy Swimming Program. “They don’t know how to use the toilet and wash their hands, or are just learning how. But we as parents can take steps to help keep our kids healthy in the water, around animals, and in childcare.”


According to the CDC, outbreaks caused by Crypto occur most commonly in the summer. It recommends the following steps to protect yourself and others:


• Do not swim or let kids swim if they have diarrhea.

• If diagnosed with Cryptosporidiosis, do not swim until two weeks after diarrhea completely stops.

• Do not swallow the water you swim in.

• Keep kids with diarrhea at home and away from childcare.

• Wash your hands with soap and water after coming in contact with animals or anything in their environment, especially animal feces. Alcohol-based hand sanitizers do not work effectively with Crypto.

• Take kids on frequent bathroom breaks, and don’t change diapers in the pool area—do so in a diaper-changing area away from the pool.

• Rinse off in the shower before getting into the water to help remove any germs on your body that could contaminate the pool water.

• Remove shoes worn in animal environments (barns, pens, etc.) before going inside your home.

• If you drink milk or apple cider, buy only pasteurized types.


Those with healthy immune systems don’t require special treatment if they contract this unpleasant bug. However, the CDC warns that those who are especially young or old or who have compromised immune systems are at increased risk for life-threatening dehydration or malnutrition. If your immune system is compromised in any way, you develop blood in your stools, are having trouble staying hydrated, or if the illness lasts longer than 10 days, be sure to let us know.

Leave a Reply

Your email address will not be published. Required fields are marked *