Scientists with the Centers for Disease Control and Prevention have released a comprehensive report detailing the incidence of recreational waterborne illnesses at splash pads, from a period spanning 1997 to 2022. The report is the first summary of waterborne disease outbreaks associated with splash pads and provides recommendations for users and operators of the facilities.
According to the report, there have been a total of 60 waterborne disease outbreaks related by health officials in 23 states and Puerto Rico. These outbreaks resulted in 10,611 individual cases of illness, leading to 152 hospitalizations, 99 emergency room visits, and no reported deaths. The authors note that the actual occurrence of waterborne illness is likely greater than what was reported for a wide variety of reasons such as misclassification and lengthy incubation periods of some of the pathogens.
A total of 9,622 cases (91 percent) and 81 percent of the hospitalizations were caused by Cryptosporidium, a parasite that can cause a severe intestinal infection. A couple of those outbreaks also included Cryptosporidium cases with Giardia or Shigella, both of which cause intestinal illnesses.
Seventy-three percent of the emergency room visits were suspected to be due to norovirus, which is the leading cause of vomiting and diarrhea in the United States.
Shigella caused a total of five outbreaks; E. coli caused three; and Campylobacter jejuni, Giardia, norovirus, and Salmonella (all stomach bugs) caused one outbreak each.
Legionnaire’s Disease, a respiratory illness, was involved in one outbreak.
For all outbreaks, a maintenancerelated contributing factor (such as a disinfectant control system that was malfunctioning, inadequate, or lacking) and inadequate water quality monitoring (such as inadequate test kits or testing frequency) were most commonly reported.
The intestinal diseases described in the report are generally transmitted by ingesting water contaminated with feces, and in most cases, those affected were children under 5. The report states that some of the common risk behaviors associated with the illnesses include sitting or standing on top of water jets, and wearing swim diapers.
“Young children can carry as much as 10 grams of feces,” the report states, and because of the splash pad’s design, this feces is washed into the water.
Meanwhile, children have been observed to place their open mouths on sprayed or jetted water and are therefore at increased risk for exposure.
Chlorine is the primary barrier to pathogen transmission, and while most bacteria and viruses are inactivated with just 1 ppm free chlorine at typical pH levels and temperatures, cryptosporidium is a different matter.
Cryptosporidium oocysts can survive for more than 7 days in water with 1 ppm free chlorine when the temperature is 77°F and the pH is 7.2–7.8, which partially explains why it was the predominant pathogen described in the report.
That said, an analysis of data from 16 jurisdictions in five states found that 10 percent of routine inspections identified violations related to inadequate disinfection levels.
CDC officials recommend that operators adhere to the 2023 Model Aquatic Health Code, which is a set of design, construction, operation, and management recommendations to prevent illness and injury associated with treated recreational water venues open to the public, and includes maintaining the water at 1 ppm free chlorine.
When it comes to preventing cryptosporidium outbreaks, the MAHC recommends using secondary disinfection systems, such as UV or ozone.
In addition to proper disinfection, preventative measures are targeted at caregivers of young children, and include carefully monitoring certain behaviors such as not allowing them to sit on water spouts, not allowing them to drink the splash pad water, taking frequent bathroom breaks, and changing them away from the water.
“Because splash pads are intended for young children, these efforts need to be oriented toward and reach caregivers of young children.”
