Jim Ariola, father of a boy who died from a rare amoeba infection, says he's struggling with the sudden death of his son.

The father of a boy who died of a suspected rare amoeba infection says he's struggling with the shock of his son's sudden death.

Jim Ariola, of Wyoming, Minn., told the St. Paul Pioneer Press for a story published Wednesday (http://bit.ly/PF8vrn ) that his 9-year-old son swam in Lily Lake in Stillwater last week. Health officials said that that's where the child likely contracted rare form of meningitis that caused his death Tuesday. The amoeba enters the body through the nose during swimming or diving and travels up a nerve to the brain.

Minnesota's only previously confirmed case was in August 2010. That child also swam in Lily Lake, which is now closed to swimming until further notice.

Ariola identified his son to the Star Tribune of Minneapolis (http://bit.ly/QMLw4P ) as Jack Ariola Erenberg. He said Jack was going to be in fourth grade this year in Stillwater, where he lived with his mother.

"It was just a fluke," Ariola told the Pioneer Press. "You can't keep kids off a beach; what the hell are you supposed to do? He loved going swimming. He was a great brother, great son," he said.

Jack had a brother and three sisters.

"He had a lot of plans coming up. Hockey was supposed to start (Wednesday) night," Ariola said.

Assistant state epidemiologist Rich Danila said he was "99 percent sure" that the boy died of primary amoebic meningoencephalitis, a parasitic infection so rare that there have been only 125 cases in the United States since 1924. It involves an amoeba called Naegleria fowleri that's found in warm freshwater. He said samples were being sent to U.S. Centers for Disease Control and Prevention in Atlanta for testing Wednesday to confirm the diagnosis.

While it's not certain that Jack or the 7-year-old victim in the previous case acquired the infections from Lily Lake, Danlia said, local authorities acting on the health department's recommendation closed it to swimming Tuesday "out of an abundance of caution. ... It's the most likely source."

Jack was traveling with his mother in Grand Marais when he fell ill Friday and rapidly deteriorated, Ariola said. He said his son became incoherent and was hallucinating, and that he was sick to his stomach and had bad headaches.

"He didn't know who was around him," Ariola said.

The boy was flown to a Duluth hospital, where a specialist contacted the CDC and the Mayo Clinic.

"They looked under the scope, and that's what they decided it was — Naegleria fowleri," Ariola said.

Ariola said his son's condition worsened Saturday.

"He didn't wake back up. They put him on a ventilator, had a machine monitoring his brain. ... His brain just started shutting down," Ariola said.

Jack was taken off life support Tuesday.

The infection is almost always fatal, Danila said. Symptoms start with headaches and move to confusion, inability to communicate, blurred vision and finally coma and death.

"It's associated with diving. The best way to decrease the risks is to wear nose clips, don't dive or hold the nose," Danila said.

All the other recorded U.S. cases have occurred south of Minnesota, with the closest case having happened in Missouri, Danila said. That's because the amoebas typically proliferate in warmer waters, though they are found in Minnesota and can go dormant and survive winter months, he said.

Danila said lakes can't be treated to kill the amoeba. He said reopening Lily Lake would likely depend on cooler temperatures, when the amoebas go dormant.

As for next year, Danila said, "we'll have to think about it. ... We'll at least put up signs to let people know the risks."

The fact that this summer has been particularly warm might have allowed the amoeba to thrive, Danila said.

"We do worry about this because we know that temperatures are increasing and we know that water temperatures are increasing," Danila said. "There's a risk but it's a very small risk, the risk would be greater for smaller, shallower areas where the water can get very hot and amoeba can proliferate."