CDC releases warning for 'crypto' fecal parasite in swimming pools

Between 2009 and 2017, there were 444 cryptosporidiosis outbreaks reported in 40 states and Puerto Rico.

Parasite-related outbreaks resulted in 7,465 individuals becoming ill. Between 2009 and 2017, there were 444 cryptosporidiosis outbreaks reported in 40 states and Puerto Rico.

Parasite-related outbreaks resulted in 7,465 individuals becoming ill. Photo: Johnny Hanson, Houston Chronicle Photo: Johnny Hanson, Houston Chronicle Image 1 of / 14 Caption Close CDC releases warning for 'crypto' fecal parasite in swimming pools 1 / 14 Back to Gallery

This Fourth of July, you might be careful before diving into your local swimming pool.

Here's why.

Health officials from the U.S. Centers for Disease Control and Prevention are reporting that there has been a recent rise in a fecal parasite called cryptosporidium or "Crypto." And that parasite can be found in swimming pools.

In swimming pools, cryptosporidium can enter the body when a swimmer ingests or swallow contaminated water.

Its effects can make even the healthiest adults endure "profuse, watery diarrhea" for as many as three weeks, according to the CDC. The parasite's impacts on children, pregnant women and those with compromised immune systems can be more harmful.

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"Crypto" and its side effects have only resulted in a single reported death since 2009. Although, 287 people were hospitalized as a result of it during that same time period, the CDC says.

The CDC report, released last Friday. explains why health officials are alarmed:

Between 2009 and 2017, there were 444 cryptosporidiosis outbreaks reported in 40 states and Puerto Rico.

Parasite-related outbreaks resulted in 7,465 individuals becoming ill.

Recreational water, primarily swimming pools and kiddie pools, resulted in 156 illnesses, over a third of the cases.

Eighty six cases involved contact with animals (primarily cattle).

Most cases were reported in the months of July and August. 2016 was the year with the most outbreaks (over 80).

The number of cases increased by an average of 12.8% per year between 2009 and 2017.

What's worse, the CDC says two factors might actually lessen the possible the number of actual cases and outbreaks.

First, the rise in cases may be the result of new testing technology. Second, the requirements for detecting and investigating and reporting cases can vary across jurisdictions.

In addition, the lone death from cryptosporidiosis came in an instance in which the parasite was transmitted via a hospital setting.

The parasite is an issue in swimming pools because an infected swimmer can excrete the parasite at "several orders of magnitude higher" than the amount necessary to cause infection.

Cryptosporidium has a high tolerance to chlorine and can inhabit in a correctly chlorinated pool for as many as seven days, according to the CDC.

According to a survey released last month by the Water Quality & Health Council, 24 percent of Americans say they've jumped into a swimming pool within an hour of having diarrhea.

There are preventative measures that can help stem the number of outbreaks.

Young, sick children with diarrhea should not be put in child care, according to the CDC.

Because chlorine bleach is an ineffective means of killing the parasite, child care workers should cleanse any and all surfaces with hydrogen peroxide.

Individuals who come in contact with livestock should take off shoes or clothing to avoid infecting environments, such their homes.

Anyone suffering diarrhea should not swim for at least two weeks and their diarrhea should no longer be present, the CDC says.

Those are are in and around swimming pools should also wash their hands thoroughly and constantly.

Note: All of the facts and information in the slides above comes from the U.S. Centers for Disease Control and Prevention and the organization's reports on this topic.

Peter Dawson is a digital reporter in Houston. Read him on our breaking news site, Chron.com, and on our subscriber site, houstonchronicle.com. | Peter.Dawson@chron.com | NEWS WHEN YOU NEED IT: Text CHRON to 77453 to receive breaking news alerts by text message | Sign up for breaking news alerts