Some deadly amoebas may be primed to invade your brain.

Naegleria fowleri (Neg-LAIR-ee-ah FOW-ler-eye) is sometimes called the brain-eating amoeba. Normally, it lives in ponds, where it dines on bacteria. But the way it seeks out meals might also make it good at crawling up our noses — and into our brains.

Naegleria amoebas are intrepid explorers. In lab studies, they probe nooks and crannies with dogged persistence. When creeping down narrow passageways, the amoebas charge relentlessly forward, almost never turning back. “They’re like robots,” says Lillian Fritz-Laylin. “They just go and go and go.”

That’s what Fritz-Laylin’s team reported on September 10 in the Proceedings of the National Academy of Sciences. A cell biologist, she works at the University of Massachusetts Amherst. She’s also an investigator at the Howard Hughes Medical Institute.

Their persistence might help these tiny, single-celled creatures make long journeys. That includes the trek from someone’s nostrils all the way to their brain. The new work offers more insight into their behavior. “We know almost nothing about the basic biology of these organisms,” Fritz-Laylin says.

N. fowleri amoebas are typically harmless to people. They usually dwell in warm bodies of fresh water. There, they squirm through mud, hunt prey and mind their own business. But on rare occasions, one can wash up a swimmer’s nose. From there, it can migrate through the nasal cavity and into the brain. Along the way, it destroys and eats tissue.

Once in the brain, it starts to reproduce, usually with lethal consequences. The United States sees fewer than 10 Naegleria infections most years. Many occur at summer swimming spots. Nearly all are fatal.

In the lab, Fritz-Laylin’s team tested how Naegleria amoebas move through different environments. Rather than N. fowleri, they used N. gruberi. This amoeba shares behaviors with its brain-eating relative but is harmless. “It’s a lot safer to work with something that can’t kill you,” Fritz-Laylin points out.

Her team placed the amoebas on glass-bottom dishes. Through a microscope, they watched the critters move around. The amoebas seemed to be interested in exploring.

The dishes held narrow microchannels. Once the amoebas bumped into a channel opening, they very rarely left it, Fritz-Laylin reports. They squeezed through channels smaller than themselves. And those tight spaces sometimes sped them up. Inside the largest channels tested, the amoebas zipped along twice as fast as cells on the outside.

Naegleria’s persistence and need for speed may make it unique. The team didn’t observe the same behaviors in a different type of amoeba that they tested. Such skills probably make Naegleria good at hunting bacteria in pond sediments, says Fritz-Laylin.

Those same behaviors, however, could also explain N. fowleri’s dark side. Put one at “the wrong place at the wrong time,” she says, “and it can cause devastating infection.”