Between 2009 and 2017, outbreaks of crypto increased by about 13 percent each year

Diarrhea-Causing Illness from Swimming Pools — Known as 'Crypto' — Is on the Rise, CDC Says

If you’re headed to the pool this summer, make sure it’s one you trust before you dive in: According to the Centers for Disease Control, outbreaks are on the rise of a diarrheal illness from swimming pools.

Outbreaks of the parasite cryptosporidium, known as crypto, have increased year after year, the CDC says in a new report. Crypto is “the leading cause of outbreaks of diarrhea linked to water,” the organization says.

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The CDC analyzed cases of crypto between 2009 and 2017, and found that there were 444 outbreaks over that span, leading to 7,465 reported cases. And during that time, the number of cases increased by an average of 13 percent each year.

Most cases — 35 percent — occurred when people swallowed water in contaminated pools or water parks. Some also came up from contact with infected cattle, and others from childcare centers.

The crypto parasite causes cryptosporidiosis, a watery diarrhea that can persist for up to three weeks.

It largely affects children aged 1 to 4, the CDC says, and young children who are not yet toilet trained and spend time in wading pools and water parks.

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To limit cases of crypto, the CDC is discouraging people from going swimming or attending daycare with diarrhea, and is instructing people to wash their hands after interacting with animals.