A person is hospitalized in St. Louis after contracting a rare infection from a deadly waterborne amoeba, the Missouri Department of Health and Senior Services reported Wednesday.
State health officials can't say for sure where the patient contracted the amoeba but said the person had been waterskiing at the Lake of the Ozarks in the days before becoming sick.
The amoeba, Naegleria fowerli, is a single-celled organism that lives in hot springs, lakes and other warm freshwater bodies and often proliferates during the hot summer months.
In the rare cases in which a person contracts the amoeba, it enters through the nasal cavity and works its way to the brain, where it causes deadly swelling called primary amoebic meningoencephalitis. That's why some people refer to it as a "brain-eating" amoeba.
Although the Centers for Disease Control and Prevention reports fewer than 170 people have contracted the amoeba since 1962, the infection is almost always fatal, with 97% of patients dying of it.
DHSS spokeswoman Lisa Cox said she couldn't give any more updates on the waterskiing patient, but said they were only the third person in Missouri to contract the amoeba since the state began keeping records. (Other Missourians were infected in 1987 and 2022.)
"If there's any positive side to this at all, it's something we have a very good grasp on how often it is happening, because it is so severe," Cox said. "It's not something that we're missing."
It's unlikely the state would outlaw swimming or other water recreation over the case, because the amoeba is so widespread in fresh water, she added.
"You'd be likely to find a positive result anywhere," Cox said. "[But] what we can do is share information about how to prevent it if people are concerned about the risk."
People can't contract Naegleria fowleri from swallowing water, only from it going into the nose. It's not spread through person-to-person contact.
To stay safe, people should hold their nose shut, use nose clips or keep their head above water when swimming or floating in warm freshwater bodies, especially when swimming, jumping or diving.
Swimmers should also avoid putting their head under the water in hot thermal springs and avoid digging in or kicking up sediment on the bottom of lakes, ponds and rivers, where the amoeba lives.
Copyright 2025 St. Louis Public Radio
