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Two acute gastrointestinal illness outbreaks were linked to a splash pad at a Kansas wildlife park, with 21 kids sickened with shigellosis and six with norovirus, a CDC report showed.

According to an investigation with Kansas state and county public health officials, both outbreaks occurred when splash pad water contaminated with feces was consumed, reported Michele Hlavsa, MPH, of the CDC's National Center for Emerging and Zoonotic Infectious Diseases, and colleagues in the .

"Outbreak contributing factors included inadequate disinfection, equipment, and training," they wrote, noting that state and county public health codes do not include regulations for splash pads, which spray water on users.

"Water stood in the collection tank (into which water drains after spraying users and before it is filtered, disinfected, and resprayed) overnight instead of being continuously recirculated, filtered, and chlorinated," Hlavsa and team wrote. "The splash pad did not have an automated controller to measure and help maintain the free chlorine concentration needed to prevent pathogen transmission. In addition, no staff member had documentation of having completed standardized operator training."

Early in the investigation, eight people with shigellosis were identified. Symptoms started within 12-73 hours of visiting the park. Two had positive stool cultures for Shigella flexneri type 1. Six were positive for the Shigella/enteroinvasive Escherichia coli target, including two positive for Shiga toxin target, though neither stool culture showed Shiga toxin-producing E. coli.

While two infected individuals reportedly visited animal exhibits, these were not tied to illness. These same individuals also used the splash pad.

The Kansas Department of Health and Environment then asked recent visitors to the park to complete an online questionnaire. Of 404 respondents, 21 experienced illness meeting the shigellosis case definition after visiting the park and six experienced illness meeting the norovirus infection case definition.

Median age of cases was 5 years, and the majority were girls. Three shigellosis patients and one norovirus patient were hospitalized; none died.

"Young children are more likely to experience acute gastrointestinal illness including shigellosis and norovirus infection, and, because of inadequate toileting and hygiene skills, are more likely to contaminate the water," Hlavsa and colleagues wrote, adding that swim diapers do not prevent contamination.

The splash pad was closed for a little over a month, and re-opened after disinfection and the implementation of an automated controller and operator training. No further illnesses were reported.

"Efforts to prevent splash pad-associated outbreaks need to be targeted to caregivers, with prevention messages that include 'Don't get in the water if sick with diarrhea,' 'Don't stand or sit above the jets,' and 'Don't swallow the water,'" the authors concluded.

They acknowledged that cases and control respondents were few in numbers, and small samples could have led to overrepresentation and bias.

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