'Hi, folks! Do you know what a freshwater amoeba is?"

That's how Jeremy Lewis greeted attendees at the Brain Health Fair who ambled up to his booth last week at the Convention Center. Then he told them about the brain-eating parasite that killed his son.

During the dog days of summer 2010, Kyle, 7, was playing in a Texas lake. At some point, a single-celled swimming monster "went up his nose and basically ate his brain," Lewis said from Booth 15. It happened fast. "Thursday morning, he had a headache. Gone on Sunday."

In a sea of booths devoted to high-profile brain conditions such as multiple sclerosis - seven Parkinson's groups alone were listed in the brochure - Lewis was among a small band of exhibitors there to talk about brain diseases deemed rare by the National Institutes of Health, meaning each affects fewer than 200,000 Americans.

Lewis was there on behalf of the Kyle Lewis Amoeba Awareness Foundation, spreading the word about a fatal brain infection, primary amoebic meningoencephalitis, or PAM. It's caused by the amoeba Naegleria fowleri. There were 31 reported cases from 2003 to 2012.

"Nobody's heard of it," Lewis says. So he and his father set up shop at the fair, held every year for opening day of the American Academy of Neurology's annual meeting.

Lewis is pressing for more research. He tells people they can reduce the threat of PAM by disinfecting pools and keeping water out of their noses. "It's all about networking, and it's about educating the public," he said.

It's also about educating doctors. Because PAM is so obscure, "it's misdiagnosed far more than it's correctly diagnosed," he said. "The doctors don't really have it in their thought process of what they're looking for."

Barbara Hunt at Booth 34 knows how that feels. "So many of our patients are misdiagnosed," she said about CADASIL, an inherited disease characterized by thickened blood vessels in the brain that block blood flow and cause strokes. "I've already spoken to no less than seven doctors who have never heard of it."

She's been attending events like this for more than two years as cofounder of the CADASIL Association and wife of a sufferer of the condition. "I feel every person that I can say the word CADASIL to, I've made a difference."

People affected by rare diseases feel isolated, she says. "You feel lonely. You feel confused."

"When you have a disease like MS, you have someplace to go. We just formed our organization two years ago, so up until two years ago, patients with CADASIL had nowhere to go."

Christina Rakshys of the National Ataxia Foundation at Booth 56 said, "We're pretty lucky if we have one support group in the whole state."

She said about 150,000 Americans have some form of ataxia, which is marked by diminished control of muscles and problems coordinating movement. It's a symptom of many disorders and can be inherited on its own.

"When people ask us what our problem is, a lot of people just say, 'Well, it's kind of like MS or Parkinson's,' because when they say ataxia, people have no idea," says Rakshys, who has hereditary ataxia. If people were more aware, she says, "maybe we can find some way to prevent and cure this stuff."

"Awareness equals money for science."