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 been sickened after using the recreational play areas over the 25 years to 2022, a CDC report found.
Of these, 152 people were hospitalized while another 99 became so ill that they went to the Emergency Room. No fatalities were reported linked to the outbreaks.
CDC scientists said the outbreaks were often caused by feces being 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 spreading 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 for regular bathroom breaks while they use the splashpads and checking diapers regularly.
People using splash pads may be at higher risk for catching disease, scientists say. Above shows adults and children using a splash pad in Arizona in July 2023 amid a heat wave
The above map shows the number of outbreaks linked to splashpads by state for 1997 to 2022
There are up to 10,000 splash pads across the US, estimates suggest, with their number surging in recent years amid attempts to cool off in the summer heat.
And outbreaks linked to the recreational areas are not common, with the number of illnesses reported — 10,000 cases in 25 years — well below the number of people who visit splash pads every year — estimated to be in the tens of thousands.
But since 1997, the recreational areas have been repeatedly linked to outbreaks of intestinal illness, 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 splashpads in 23 states and Puerto Rico from 1997 to 2022.
Overall, they detected 60 waterborne disease outbreaks linked to the pads during this time — leading to the cases and hospitalizations.
Of the 52 outbreaks with data available, 40 were caused by Cryptosporidium hominis, an easily transmitted single-celled micro-organism that thrives in water and can cause prolonged watery diarrhea, stomach cramps and a high fever.
Analysis showed it caused 9,622 of the infections linked to splash pads — or 91 percent of the total — and 123 hospitalizations — or 81 percent. And was linked to the three largest outbreaks, which led to 2,307 cases, 2,050 cases and 2,000 cases.
It caused another outbreak this year, when Albuquerque in New Mexico was forced to shutter its water parks because of a spate of illnesses linked to micro-organisms.
C. hominis causes symptoms such as watery diarrhea and stomach cramps, with sicknesses normally clearing up in a few days. In severe cases, it can cause chronic life-threatening diarrhea with severe dehydration and wasting of muscles.
The above shows the splash pad outbreaks by the month they were reported from 1997 to 2022
There were also five outbreaks caused by Shigella, three caused by E.coli and one each caused by norovirus, salmonella and two other pathogens.
No outbreaks were linked to the brain-eating amoeba naegleria fowleri, but in September last year a toddler in Arkansas was reported to have died from the disease after playing in a local country club’s splashpad.
By state, Ohio and Florida recorded the most outbreaks over the study period — at 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 from June to September, when people are also most likely to use splash pads.
Describing how the water became contaminated, report lead authot Hannah Lawinger — an epidemiologist — and others said: ‘Young children also are less likely to have mastered toileting skills and hygiene skills, and swim diapers do not prevent fecal contamination of recreational water.
‘Sitting or standing on top of water jets… are behaviors commonly observed in children playing in splash pads. [But] the former behavior results in rinsing of diapers or perianal surfaces, which in young children can carry as much as 10 grams of feces.
‘Thus, because of their design, splash pads can be at increased risk for contamination with pathogens.’
Regulations require splash pads to maintain chlorine levels at about one part per million, which is the normal threshold for killing off most diseases.
But researchers said spraying the water can aerosolize chlorine, decreasing its concentration. C. hominis also has some tolerance to the chemical.
