A new scientific study threatens to cast a pall over the summer cannonball season.
Researchers with the U.S. Geological Survey and other organizations have detected Naegleria fowleri, aka "brain-eating amoeba," in the waters of three hugely popular sites in the National Park System.
The nature reserves in question: Grand Teton National Park in Wyoming, Lake Mead National Recreation Area in Nevada, and Yellowstone National Park in Wyoming, Montana, and Idaho.
The amoeba, which lives in warm fresh water, can cause a rare but lethal infection called primary amebic meningoencephalitis (PAM).
Humans can develop the infection when water containing the amoeba enters the nasal cavity and the microscopic organism finds its way to the central nervous system and brain, where it earns its frightening nickname.
Most cases arise following swimming, diving, or otherwise recreating in warm fresh water. The amoeba does not live in salt water.
"Brain infections caused by Naegleria fowleri are very rare but nearly always fatal," according to the Centers for Disease Control and Prevention.
In the new study, researchers detected the amoeba in more than a third (34%) of water samples taken from the three parks.
Should we start freaking out about this?
As SFGate points out, "Many of the sites tested were remote geothermal areas or low-use thermal waters rather than heavily trafficked swimming beaches or major recreation hubs."
In other words, your brain should remain safe from any amoebas lurking in a boiling hot spring you can't jump into anyway.
Still, the study's authors conclude that their findings indicate that Naegleria fowleri is present in more thermally impacted areas across the western United States than previously assumed, underscoring the importance of "enhanced monitoring, public awareness, and risk management strategies in thermally influenced recreational waters."
As rare as PAM cases are, they do happen. In 2022, a teenager died from the infection after swimming in Lake Mead, one of the areas cited in the new research.
And as temperatures get warmer around the world, evidence suggests the geographic territory of the dangerous creature has expanded. It thrives in warm water, after all, and there's more of that than ever nowadays.
Are there ways to reduce the risk?
The CDC recommends holding your nose or even wearing a nose clip when jumping or diving into fresh water.
Low-cost clips can be purchased for less than $10.
Note that the risk of infection is higher, according to the CDC, "when it's been hot for long periods, resulting in higher water temperatures and lower water levels."
So be extra careful during the dog days of summer.
And if you take a soak in natural hot springs at any time of the year, it's a good idea to keep your head above the water the whole time.