Testing for a fatal amoeba in the Whitewater Center’s signature channel came back with unusually high numbers, according to the federal Centers for Disease Control and Prevention, and the Whitewater Center has put its cleaning on hold to figure out what to do.
It is still true, however, that infections are rare and that the risk can never be completley eliminated.
Here’s the background: Testing started last week to determine whether or not the “brain-eating” amoeba, Naegleria fowleri, responsible for a young woman’s recent death, came from the Whitewater Center.
[Related story: The state legislature is getting involved with the Whitewater Center]
The results of the CDC’s testing were finalized Thursday afternoon, with unusually high numbers.
Each of the 11 samples taken from the whitewater channel came back positive, confirming a significantly high presence of the pathogen in the Whitewater Center’s water.
To put it in perspective, four samples taken from the Catawba River were confirmed negative and only one sample from the river’s sediment was positive.
“Our findings here at the Whitewater Center are significant in that we saw multiple positive samples,” a representative from the CDC said via Skype. “As well as levels we hadn’t previously seen in environmental samples.”
It will be something that they will need to study further, she added.
While the CDC did not measure the concentration of the amoeba, the tests provide a general indication of the levels of concentration.
High levels of concentration don’t have to mean that there’s a larger chance of getting sick, however.
That type of correlation is a hard one to pinpoint, said Mecklenburg County Medical Director Dr. Stephen Keener, who added that the lack of medical literature and data on the subject make it hard to be able to say that yes, an increased concentration leads to an increased risk.
Variables like soil runoff, stones with slime layers, recirculating water and shallow channels all could have made the presence of the amoeba possible.
But it’s important to remember infection is rare, as Keener pointed out, and that “hundreds of millions of visits” to open bodies of water nationally have resulted in fewer than eight infections in a year.
The number of positive samples and the concentration levels moved the CDC to call the filtration system at the Center “inadequate” when it comes to inactivating the amoeba – because the filtration methods they used are, normally, enough to kill it.
The amoeba can be killed with the use of “adequate chlorination and UV light,” according to the CDC, but the turbidity of the water rendered both of those methods useless.
“Some things that affect both chlorine and UV light is the amount of dirt and debris that is in the water,” the CDC representative explained. “[It] affects the clarity of the water, and the water at the Whitewater Center is fairly, what we call, ‘turbid.’ There’s a fair amount of debris in there.”
When water reaches a certain level of turbidity and chlorine or UV light is added to it, there’s a reaction with the debris that automatically consumes both, meaning that both essentially disappear from the water and can’t play a role in inactivating the amoeba.
That being said, it’s “hard to say” if less turbidity could have allowed the amoeba to be killed, the CDC added.
Because of the numbers, the cleaning process has been put on hold while they find a way to clean that is more effective and safer for the Whitewater Center employees, officials said Thursday.
The process of draining, chlorinating and pressure washing the whitewater channels seemed like the “next logical step” according to a CDC representative, but the volume was high enough to get their attention. They have consulted occupational health experts to find a better, safer method in order to protect workers.
The County Health Department, Division of Public Health in Raleigh and the CDC are all working together to figure out what the next step is.
The goal is to come up with realistic solutions that will, in turn, create an effective system that will keep the environment safe for the public to use. It will take experts “beyond” the CDC and various sectors to formulate a plan for how to address this.