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Ready to Dive into a Pool of Disease-Causing Parasites?

Written by Michelle Udayamurthy, M.D. on Jun 16, 2018, 9:45:00 AM

School is out, so there’s a good chance you and your family are planning a vacation soon – and I bet you’re looking forward to that! What’s not inviting about a resort where you can relax, not worry about doing dishes or laundry, and unwind in a pristine pool for however long you choose? Except there may be more than meets the eye with respect to the “pristine” pool, such as invisible parasites and bacteria that, according to the Centers for Disease Control and Prevention, were responsible for nearly a third of recreational waterborne disease outbreaks between 2000 and 2014. Who’s ready to jump in? 

Lurking Under the Surface

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You read that correctly. Swimming pools all over – backyard pools, waterpark pools, motel pools, and even five-star resort pools – can carry parasites and bacteria that can make you pretty sick. A common parasite found in pools is Cryptosporidium (also referred to as “Crypto”), a microscopic parasite that causes cryptosporidiosis. This is a disease characterized by vomiting, diarrhea, dehydration, lack of appetite, weight loss, stomach cramps or pain, nausea, and fever. When someone swallows water where these parasites are living, the parasites travel through that person’s body until they reach the small intestine, where they burrow into the walls and make a short-term home. Typically, people suffer through diarrhea, and the infection takes care of itself in a week or two, but anyone with a compromised immune system can experience serious health problems as a result of Crypto. In fact, it even can be life threatening in these individuals. In other cases, regardless of the health or status of your immune system, symptoms can come and go for up to a month. 

Chlorine Can’t Kill Some Parasites

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Here’s the thing about pools. A well-maintained swimming pool is less likely to become a breeding ground for parasites and different types of bacteria than one that is largely ignored. So chances are, you’re more likely to develop infections in places where the chlorine and pH levels aren’t properly maintained. But, here’s the thing about Crypto: It’s a tough parasite. It can live and thrive in pools that are carefully maintained. These parasites do quite well in pools of all kinds, and they thrive especially well in lakes and streams. So while a good-looking and balanced pool might keep you safe from many different types of bacteria, it’s not necessarily a deal-breaker for Crypto. 

How to Avoid Parasites in Pools

Crypto is contagious and spreads when the parasites are shed through feces, which is why it spreads easily in water. To avoid infection, avoid contact with anything that has come in contact with feces. This is good advice regardless of what bacteria or illness you’re trying to avoid, isn’t it? So when you’re swimming in an unfamiliar pool (with people who might or might not be infected), don’t drink the water. And if you think you or someone in your family might be infected, stay out of the pool until your symptoms and the disease is gone.


Dr. Michelle Udayamurthy is a board-certified Internal Medicine physician at Kelsey-Seybold. She cares for her patients at the Spencer R. Berthelsen, M.D., Main Campus. She views the doctor-patient relationship as one of the most important parts of healthcare. Her clinical interest is preventive medicine. 


Topics: swimming pool parasites, swimming pools disease, swimming pools germs, swimming pools bacteria

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