A federal epidemiologist said Thursday that filtration and disinfection systems at the U.S. National Whitewater Center were inadequate to properly clean the facility’s turbid waters.
Dr. Jennifer Cope said that results of all 11 water samples from the center detected the presence of an amoeba that infected and killed an Ohio teenager on June 19 who had previously rafted at the center.
She called the results “significant” and at levels the Centers for Disease Control and Prevention had not previously seen. Water samples from the nearby Catawba River were negative, but the amoeba was found in river sediment.
Cope’s agency, the CDC, had preliminarily confirmed the presence of the amoeba at the park. The center shut down rafting on its whitewater channels last Friday but continues other activities.
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Thursday night, the state House of Representatives unanimously passed a bill, which requires mandatory testing of the center’s water, according to WBTV, the Observer’s news partner.
The Whitewater Center filters its water and applies ultraviolet radiation to kill disease-carrying microbes. Those systems, Cope said, “were inadequate for (the Naegleria fowleri amoeba) in that setting.”
Organic material in the water could interfere with the systems, she added. Such material reacts with chlorine, a commonly used disinfectant, and renders it useless.
The amoeba levels found in the center’s water, Cope added, were “significant at levels we haven’t previously seen in environmental samples.” Those levels were higher than those seen in warm freshwater, where the amoeba is common.
Infections occur when water goes up the nose. The Whitewater Center, where Ohio teen Lauren Seitz overturned in a raft June 8, was the only such exposure she had before dying, Cope said.
The investigation that followed Seitz’s death is largely focused on what changes are needed at the center rather than the circumstances that led to her exposure to the amoeba, said Dr. Stephen Keener, medical director of the Mecklenburg County Health Department.
Health officials say they have not fully reviewed the center’s water treatment operating records.
“There is a lot being questioned going forward,” Keener said, “but we have not reached any conclusions as yet.”
Keener said “it’s pretty clear” that the center’s treatment system isn’t sufficient to protect public health. “It’s very, very important for us to understand what will work.”
Health officials said visitors who took part in whitewater activities at the center before Friday should be aware of infection symptoms including headache, fever, nausea and vomiting, progressing to neck stiffness, confusion or loss of balance. Symptoms appear one to seven days after exposure. Infections are extremely rare but usually fatal.
Cope added: “Moving forward, there are ways to make this water less conducive to Naegleria growth.” Among them are reducing the amount of organic material in the water and addressing warm water temperatures, which encourage the growth of microorganisms.
The Observer reported Sunday that the Whitewater Center is the only one of three similar artificial rivers in the U.S. that is not regulated to ensure its water is safe. The center’s only requirement, for weekly bacteria checks, is stipulated under a lease agreement with Mecklenburg County.
The N.C. House gave tentative approval Tuesday to a measure that would regulate the Whitewater Center for the first time.
The N.C. Department of Health and Human Services “supports Mecklenburg County and its health officials in finding and achieving a solution for the U.S. National Whitewater Center,” Dr. Randall Williams, the state health director, said in a statement Thursday. “Understandably, this is a serious situation that requires a deliberate and collaborative approach to determine the next course of action.”
The Whitewater Center says on its website that it will drain water from the channels to dry them, clean all concrete and rock in the channels and test both its wells and city water supply for the amoeba. It’s not clear when the channels will reopen.
In a prepared statement, the center said it will work with health officials on additional water quality measures to minimize risks from the amoeba but said it does not expect to eliminate them.
“The objective is to develop a water quality program that improves our chances of reducing the risk of exposure to Naegleria fowleri and provide better overall water quality,” the statement said. “We will have a better estimate on the time frame as we move forward.”