A Child’s Death From Naegleria fowleri Traced to a Poorly Disinfected Splash Pad

Naegleria fowleri is a free-living ameba found in warm fresh water and soil. When water carrying it goes up the nose, it can cause primary amebic meningoencephalitis (PAM), a rapidly destructive brain infection. PAM is rare and often fatal: of 164 people known to have been infected in the United States during 1962–2023, only four (2.4%) survived. Most infections follow swimming or diving in fresh water such as lakes in summer. This CDC report describes a death linked to a splash pad — a play area that sprays or jets water on children and has little or no standing water.

The case

On September 1, 2023, a previously healthy 16-month-old was brought to an Arkansas hospital after 3 days of fever, vomiting, eating and drinking less, lower activity and a newly altered mental state. A head CT scan suggested raised pressure inside the skull. Doctors started treatment for bacterial and viral meningitis and admitted the child to intensive care. The spinal fluid looked like bacterial meningitis, but a multi-pathogen test was negative and cultures grew nothing. The child grew worse.

On September 3, a pathologist examining stained spinal-fluid slides found numerous amebas that looked like Naegleria. The family said the child had played at a splash pad and pool in Pulaski County on August 26 and 27, 2–3 days before falling ill. Doctors began treatment for N. fowleri — amphotericin B, azithromycin, dexamethasone, fluconazole, miltefosine and rifampin — and alerted CDC and the Arkansas Department of Health. The child died on September 4. On September 6, CDC confirmed N. fowleri in the spinal fluid by PCR.

The splash pad

A state environmental health specialist inspected the site on September 3. The splash pad recirculated its water: a pump drew water from an underground tank to spray nozzles in the deck; the water ran down a sloped surface into a perimeter drain and back to the tank, where another pump sent it through a sand filter, a chlorinator and an acid feeder. Its source was city tap water, sometimes topped up by hose from the pool.

Schematic of the splash pad’s water system. Image from CDC’s report.

Inspectors found multiple code violations:

• the water’s pH was above the test kit’s limit of 8.2 (the state allows no more than 7.8, and higher pH weakens chlorine)
• chlorine was above the kit’s 5 ppm limit
• the chlorinator had reportedly not worked for about a month, and chlorine was being added by hand each day — a practice that gives uneven disinfection
• no daily operating records were kept

The pool had problems too: pH above 8.2, a faulty flow meter, water from a large equipment-room leak being pumped into the surge pit, and no records. Both were closed.

Confirming the source

Swabs and water samples went to CDC. On September 13, live N. fowleri grew from a swab of the splash pad tank. Other amebas were found in water from the tank and the pool, though not Naegleria. On September 28, genetic typing showed the ameba from the child and the one from the tank were both genotype III. Together, the evidence pointed to the splash pad as the most likely source. It was permanently disabled; the pool’s violations were corrected and it received a new permit after an inspection on June 3, 2024.

An emerging risk

In 2020–2021, two children in Texas died of PAM after playing at separate “splash pads” with poorly disinfected water — one a decorative fountain the public used as a splash pad, the other a recirculating splash pad that was not properly monitored. This Arkansas death is the third such case in 4 years. With no records and a failed chlorinator, the authors say poor disinfection may have been a chronic problem — and over time that allows biofilm to grow, feeding amebas and shielding them from disinfectant.

Lessons

For clinicians: PAM is hard to diagnose because early signs, and even spinal-fluid results, can mimic bacterial meningitis. Consider it in anyone with acute meningoencephalitis and recent water up the nose — including treated water in splash pads or pools. Stains such as Wright-Giemsa can reveal the ameba; a Gram stain is not enough, because heat-fixing can destroy it. Confirmatory tests are available at selected laboratories, including CDC’s. Prompt diagnosis and treatment are critical.

For operators: CDC’s voluntary Model Aquatic Health Code recommends, among other things:

• free chlorine of at least 1.0 ppm (2.0 ppm with cyanuric acid), or total bromine of at least 3.0 ppm
• pH between 7.0 and 7.8
• testing disinfectant and pH before opening each day and every 2–4 hours while open
• a daily inspection that checks disinfection, recirculation and filters, and removes biofilm from the tank, nozzles and drains
• water turnover in 30 minutes or less, drains that prevent standing water, and regular tank cleaning
• written records of testing, responses and maintenance

PAM is not nationally notifiable, but CDC tracks cases with health departments’ voluntary help.

Sources

Based on Dulski TM, Montgomery F, Ramos JM, et al., "Fatal Case of Splash Pad–Associated Naegleria fowleri Meningoencephalitis — Pulaski County, Arkansas, September 2023," MMWR Vol. 74, No. 10, CDC, with the passages cut off in the imported copy completed from the same report in PubMed Central (PMC11949314); a work of the United States government in the public domain. Diagram from the same report.