Parents are being advised to take extra precautions at splash pads next year after they were linked to a surge in illnesses.
More than 10,000 children and adults have become ill after using the recreational playgrounds over the past 25 years through 2022, a CDC report shows.
Of these, 152 people were hospitalized, while another 99 became so ill that they went to the emergency room. No fatalities linked to the outbreaks have been reported.
CDC scientists said the outbreaks were often caused by feces released from children’s diapers and contaminating the water.
Splash pads do contain chlorine to prevent outbreaks, but this is often aerosolized by spray jets, making it less effective.
To prevent the spread of disease to others, they said families should not visit splash pads for two weeks after a child suffers from diarrhea.
They also suggested taking children to the toilet regularly, using the splash pads and checking diapers regularly.
People who use splash pads may be at greater risk of contracting diseases, scientists say. Above are adults and children using a splash pad in Arizona during a heat wave in July 2023
The map above shows the number of outbreaks associated with splash pads by state for the period 1997 to 2022
There are about 10,000 splash pads in the U.S., estimates show, and their numbers have skyrocketed in recent years due to efforts to cool off in the summer heat.
And outbreaks linked to the recreation areas are infrequent, with the number of reported illnesses — 10,000 cases in 25 years — well below the number of people who visit the splash pads annually — estimated in the tens of thousands.
But since 1997, the recreational areas have repeatedly been linked to outbreaks of intestinal diseases, with symptoms including watery diarrhea, stomach cramps and fever.
For the report, published in the CDC’s MMWR, the agency analyzed data on disease outbreaks linked to splash pads in 23 states and Puerto Rico from 1997 to 2022.
In total, they discovered 60 waterborne disease outbreaks linked to the pads during this period, leading to cases and hospitalizations.
Of the 52 outbreaks for which data are available, 40 were caused by Cryptosporidium hominis, an easily transmissible single-celled microorganism that thrives in water and can cause prolonged watery diarrhea, stomach cramps and high fever.
Analysis found it caused 9,622 of the infections linked to splash pads – or 91 percent of the total – and 123 hospital admissions – or 81 percent. And was linked to the three largest outbreaks, which led to 2,307 cases, 2,050 cases and 2,000 cases.
The disease caused another outbreak this year when Albuquerque, New Mexico was forced to close its water parks due to a wave of illnesses linked to microorganisms.
C. hominis causes symptoms such as watery diarrhea and stomach cramps, with the illnesses normally clearing up within a few days. In severe cases it can cause chronic life-threatening diarrhea with severe dehydration and muscle wasting.
The above shows splash pad outbreaks in the month they were reported from 1997 to 2022
There were also five outbreaks caused by Shigella, three caused by E.coli and one caused by norovirus, salmonella and two other pathogens.
No outbreaks have been linked to the brain-eating amoeba naegleria fowleri, but last September it was reported that a toddler in Arkansas died from the disease after playing on the splash pad at a local country club.
By state, Ohio and Florida recorded the most outbreaks during the study period – eight outbreaks each – followed by West Virginia, which reported three outbreaks.
Arizona, California and Idaho each reported three outbreaks, while Utah, Colorado, Texas, Louisiana, Missouri, Tennessee, New York and Massachusetts reported two.
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Washington, Kansas, Oklahoma, Illinois, Alabama, Georgia, South Carolina and Pennsylvania each recorded one outbreak.
Outbreaks were most common during the summer months of June to September, when people are also most likely to use splash pads.
Describing how the water became contaminated, lead author Hannah Lalinger – an epidemiologist – and others said: ‘Young children are also less likely to master toileting and hygiene skills, and swim diapers cannot prevent fecal contamination of recreational water.
‘Sitting or standing on water jets… is a behavior commonly observed in children playing in splash pads. (But) the first behavior results in rinsing of diapers or perianal surfaces, which can carry as much as 10 grams of feces in young children.
“So because of their design, fenders may be at increased risk of contamination with pathogens.”
Regulations require splash pads to keep chlorine levels at about one part per million, which is the normal threshold for killing most diseases.
But researchers said spraying the water can aerosolize chlorine, reducing its concentration. C. hominis also has some tolerance to the chemical.