02/07/2019 1:52 AM AEST | Updated 06/07/2019 4:30 AM AEST

Fecal Parasite Found in Public Swimming Pools On The Rise, CDC Warns

Cryptosporidium can survive for days in chlorinated water and cause watery diarrhea for up to three weeks.

A fecal parasite that sickens people through contaminated swimming pool water is on the rise across the U.S., prompting federal health officials to warn the public to take extra precautions this summer.

Cases of cryptosporidiosis, which can cause watery diarrhea for up to three weeks, have been increasing by 13% every year, the Centers for Disease Control and Prevention said Friday.

The parasite behind the outbreak, cryptosporidium, is spread by bathers who have or have had diarrhea within the last two weeks. But unlike other germs, this parasite can survive in well-maintained chlorinated pools for up to a week. 

This 1983 microscope image provided by the Centers for Disease Control and Prevention shows Cryptosporidium parvum parasitic organisms in a stool smear specimen, the cause of a patient's cryptosporidiosis.

“People have an average of 0.14 grams of poop on their bottoms. This poop can wash off swimmers’ bodies and can contaminate the water with germs,” the CDC warns.

It only takes microscopic amounts of this infected fecal matter to contaminate an entire pool or hot tub. If a public swimming facility uses one filtration system for more than one pool, it could spread to all of them.

“This means that a single diarrheal incident from one person could contaminate water throughout a large pool system or waterpark,” the CDC states. “That is why it is so important to stay out of the pool if you are sick with diarrhea, shower before swimming, and avoid swallowing pool water.”

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Health officials urge bathers to shower before entering a swimming pool, to not swallow any water and to not swim if they have or have had diarrhea within the last two weeks.

The CDC recommends taking a swimming break every hour so that everyone can use the bathroom, reapply sunscreen, drink fluids and check and change diapers.

However, waterproof swim diapers will not necessarily stop the parasite’s spread if the child is ill, said Dr. Chris Nyquist, a pediatric and infectious disease specialist at Children’s Hospital Colorado.

“The thing that they’ll do is they’ll keep solid poop in their diaper but they’re not going to keep from spreading infection or getting an infection,” Nyquist told HuffPost. “If you do have swim diapers you should be getting kids out of the water every 60 minutes or so to clean the diapers and wash your hands.”

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Parents are advised to give their kids pool breaks every hour so they can use the bathroom, drink water, and have diapers checked and cleaned.

As for older children and adults, showers also aren’t a guaranteed solution for those who have or have had diarrhea after contracting the parasite.

“When you’re a normal healthy kid your immune system will clear it out but you can still spread the cysts,” she said. “You should really delay going into pools for a couple of weeks because you can still shed it.”

Nyquist urged parents to “not be scared out of their mind” this summer but to exercise common sense practices, stating: “If everyone does their part that’s what will keep it from spreading.”

The reported increase in cases by the CDC follows a review of 444 cryptosporidiosis outbreaks within 40 states and Puerto Rico from 2009 to 2017, with cases peaking during the summer months of July through August. This amounted to 7,465 cases, 287 hospitalizations, and one death, the CDC said.

Cases of cryptosporidiosis have been rising annually, the CDC warns. Most of them come from infected swimming pools, farm animals and then childcare.

In addition to contaminated swimming pools, the parasite is commonly transmitted by contact with infected cattle and contact with infected children.

Children, pregnant women and those with compromised immune systems are at greater risk of severe or life-threatening illness from the parasite.

This story has been updated with comments from Dr. Chris Nyquist

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