Story highlights Unusually high levels of brain-eating amoeba found in all 11 water samples

Dirty water is the likely cause of the failure of the water park's sanitation system

Whitewater channel of park remains closed until it can be cleaned

(CNN) Levels of the brain-eating amoeba Naegleria fowleri, which killed an Ohio teen, were unusually high in water samples taken from the U.S. National Whitewater Center and were probably caused by the failure of the water sanitation system, the Centers for Disease Control and Prevention announced this week.

All 11 samples from the whitewater area of the park tested positive for the potentially fatal organism, the CDC said. Other samples from the nearby Catawba River were negative, although the amoeba was found in one sample of riverbank sediment.

"Our findings here are significant," said Dr. Jennifer Cope, an infectious disease physician at the CDC. "We saw multiple positive samples at levels we've not previously seen in environmental samples."

The amoeba was probably able to grow to such concentrations because of the amount of dirt and debris in the water, which turned the water "turbid" or murky and interfered with the effectiveness of the sanitation process, Cope said.

"When you add chlorine to water like that, the chlorine reacts with all that debris and is automatically consumed," explained Cope. "It is no longer present to inactivate a pathogen like Naegleria."

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