The US National Whitewater Center (USNWC) has shut down rafting activities after an Ohio teenager was killed by a brain-eating amoeba.
18-year-old Lauren Seitz died last Sunday of a rare brain infection after she was exposed to the amoeba at the North Carolina waterpark where she went with a church group earlier this month.
According to officials from the Centers for Disease Control and Prevention (CDC), the infection was caused by the amoeba naegleria fowleri.
"Initial test results found naegleria fowleri DNA was present in the whitewater system," the USNWC said in a statement.
At a press conference, Mecklenburg County health director Marcus Plescia said most of 11 samples tested by the CDC this week showed preliminary evidence of the amoeba.
"On behalf of the USNWC, I wish to express our sincere condolences and sympathies to Lauren and her family," chief executive Jeffrey Wise said in a separate statement. "Our focus is always on stressing safety and risk in the most appropriate manner possible."
State health officials noted that the amoeba is common in warm lakes, rivers and springs in summer, and said in a statement that it does not cause illness if swallowed, but can be fatal if forced up the nose. The one-celled organism does not survive in saltwater and cannot infect a person who drinks contaminated water.
In the event of brain infection, the amoeba causes illness up to nine days after exposure. Symptoms include headache, fever, vomiting, confusion, seizures, loss of balance and hallucination.
Death usually follows within five days. The fatality rate, according to the CDC, is more than 97%.
According to the USNWC, Seitz’s "only known underwater exposure was believed to be when riding in a raft with several others that overturned" at the center.
State and CDC officials are investigating the death with the center’s cooperation.
The USNWC’s water is sourced by county utilities and two wells on its premises. Wise said the water is disinfected with ultraviolet radiation, filtered and periodically given a dose of chlorine.
It has weekly water tests carried out by a third-party lab, he added.
But Wise admitted inherent danger.
“Despite every measure we take, there is always a risk of injury or harm based on the very nature of what we do and who we are,” he said. “We are deeply saddened any time harm occurs as a result.”
The center remains open for activities unrelated to the whitewater rafting.
Health officials said people should hold their noses shut or keep their heads above water when in warm freshwater areas, and should avoid water activities at times of high temperature and low water levels.
The amoeba can also be found in sediment and wet soil, meaning people should avoid digging or disturbing sediment in areas where the organisms are often found.