Chlorine Does Not Kill This Resilient Parasite That May Be Lurking in Your Pool

Proactive Health


By Joy Stephenson-Laws, JD, Founder

There may be something in your swimming pool. And I’m not talking about inflatable pool toys and floats. It  may be a parasite called Cryptosporidium. The Centers for Disease Control and Prevention (CDC) recently released a report warning people about Cryptosporidiosis outbreaks.

What is Cryptosporidiosis?

Cryptosporidiosis is a diarrheal disease caused by Cryptosporidium. Both the disease and parasite are called “Crypto” for short. According to the CDC, Crypto is “is the leading cause of outbreaks of diarrhea linked to water and the third leading cause of diarrhea associated with animal contact in the United States.”

Furthermore, “The parasite is protected by an outer shell that allows it to survive outside the body for long periods of time and makes it very tolerant to chlorine disinfection.”

The parasite can survive in a chlorinated pool for up to seven days!

Leading causes of Crypto include swallowing contaminated water in pools or water playgrounds, contact with infected cattle and contact with infected persons in child care settings. Crypto can also be a foodborne illness.

Crypto lives in the gut of infected humans or animals. An infected person or animal sheds Crypto parasites in their poop. An infected person can shed 10,000,000 to 100,000,000 Crypto germs in a single bowel movement. Shedding of Crypto in poop begins when symptoms like diarrhea begin and can last for weeks after symptoms stop. Swallowing as few as 10 Crypto germs can cause infection,” according to the CDC.

So basically (to give you an example) if a child is swimming with a dirty diaper or an adult has traces of fecal bacteria on their body and jumps in the pool, we may have a problem.

The CDC’s report says:

  • Between the year 2009 to 2017, there were 444 Crypto outbreaks which resulted in 7,465 cases that were reported by 40 states and Puerto Rico.


  • Out of these 7,465 cases, 4,232 of them were attributed to contaminated recreational water such as pools and water playgrounds.


  • Number of reported outbreaks has increased an average of 13 percent per year (which is why people need to be proactive).


What’s especially noteworthy is that the CDC said most of these Crypto cases were reported during the months of July and August (peak summer months). So now that summer has officially started, we have to be especially mindful and proactive about Crypto.

Crypto just doesn’t make you a bit “under the weather” with an upset stomach. In some cases, Crypto may cause profuse, watery diarrhea that can last up to three weeks in some patients. It can be especially bad in children, pregnant women and people with compromised immune systems. The CDC says that in more severe cases Crypto could lead to life-threatening malnutrition. 

And for all of us, prolonged diarrhea may cause dehydration and nutrient loss.

“Prolonged diarrhea can cause dehydration, weakness, fatigue, and weight loss. When you have diarrhea, important nutrients such as protein, vitamins, water, sodium, and potassium are lost. This loss can be serious if you are already ill or trying to recover from an illness,” reports the Cleveland Clinic

Luckily, Crypto has not caused many deaths (one death has been reported since 2009). But you can probably imagine how unpleasant Crypto can be and that this is a disease you definitely want to try to avoid this summer. Symptoms of Crypto can come and go for up to 30 days, and aside from diarrhea, symptoms may also include nausea, vomiting (which may also cause dehydration and nutrient loss issues), stomach cramps, fever and more.

So how can you be proactive?

  • If your child is sick with diarrhea, do not put them in child care. 


  • If there is a Crypto outbreak in a child care center, surfaces should be wiped down with hydrogen peroxide (chlorine bleach is ineffective at killing this parasite).


  • If you are someone who comes into contact with livestock, it is extremely important to wash your hands and wash the clothes you were wearing when you came into contact with the animals. Keep shoes worn during animal contact outside of your home.


  • If you have diarrhea, do not visit communal pools. In fact, you should wait at least two weeks to go swimming after your diarrhea subsides.


  • Always wash your hands (use warm soap and water and wash for at least 20 seconds) after using the bathroom, changing a dirty diaper and gardening (even if you wear gloves).


  • Try to not swallow pool water.


  • When you are at the pool with your kids, take them on frequent bathroom breaks and if your child is in diapers, check the child’s diaper often to see if it needs to be changed.


  • Make sure your immune system is in the best shape that it can be. Read here to learn about specific vitamins and minerals that may help boost your immunity.                 


It is also extremely important to avoid nutritional deficiencies. One of the ways you can do this, in addition to eating a variety of healthy foods, is to get a comprehensive nutrient test to determine whether you have any nutrient deficiencies or imbalances. If you do, you may have to tweak your diet and take good quality supplements, which a competent healthcare professional can assist you with.

Finally, if you happen to get Crypto or suffer from dehydration, vomiting and diarrhea, consider utilizing IV vitamin drips and injections to replenish lost nutrients. And as always, seek medical attention to get a proper diagnosis and devise a treatment plan.

Have a safe and healthy summer, and enjoy your healthy life!


The pH professional health care team includes recognized experts from a variety of health care and related disciplines, including physicians, attorneys, nutritionists, nurses and certified fitness instructors. This team also includes the members of the pH Medical Advisory Board, which constantly monitors all pH programs, products and services. To learn more about the pH Medical Advisory Board, click here.  


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