CDC says diarrhea-inducing parasite on the rise in US pools

If you're planning to take a dip in a pool this summer, make sure to plug your nose and close your mouth. Any inadvertent ingestion of even chlorinated pool water could wind up giving you cryptosporidium. More simply known as "crypto," the microscopic parasite can make otherwise healthy adults and children feel incredibly sick with stomach cramps, nausea and bouts of diarrhea that can last up to three weeks.

This isn't a new parasite, but according to the Centers for Disease Control and Prevention, the number of recorded crypto outbreaks has doubled at U.S. pools and water playgrounds in two years. In 2014, there were 16 outbreaks, according to data published by the CDC's Morbidity and Mortality Weekly Report on Thursday. In 2016, there were 32.

Ohio was one of the most heavily-infected states, according to the CDC, with 1,940 people falling ill due to the infection in 2016 compared to less than 600 in any previous year.

Before you cancel your child's swim lessons, however, the CDC said it's not sure what accounts for the rise in recorded outbreaks.

"It is not clear whether the number of outbreaks has increased or whether better surveillance and laboratory methods are leading to better outbreak detection," it said in a press statement.

Once a pool or water playground is infected with crypto, it's easy to spread, but not easy to get rid of. It can survive up to 10 days in properly chlorinated water, and it takes just a swig to get sick. The only way to ensure the health of the water once its been infected is to close the pool and treat it with extremely high levels of chlorine that are dangerous for humans to swim in.

Meanwhile, the only way to ensure your own health is to take precautions when swimming in pools or playing at water parks. The CDC recommends avoiding swallowing any water and rinsing off in the shower once you get out.

Public health experts also say people can help contain the germs by avoiding the pool while sick and waiting two weeks after symptoms subside from a suspected case of crypto before going swimming.

The rise in crypto cases shouldn't necessarily deter recreational swimmers, however.

"I will continue to swim in pools," Prof. Kellogg Schwab, the director of the Johns Hopkins University Water Institute, said Friday. He underlined, however, he will also be following a few "common sense" guidelines to make sure the pools he swims in remain healthy environments.

While the CDC recommends everyone shower to decrease the amount of organic matter someone might transfer into pool water, Schwab adds that people should also pay special attention to their hands.