Arguments Friday in a wrongful-death suit filed after a microscopic amoeba killed a 9-year-old boy who had been swimming in Stillwater’s Lily Lake last summer turned on the limits of government’s responsibility about warning the public of dangers at recreational sites.

The Minnesota Department of Health, Washington County and the city of Stillwater are being sued by James Ariola, the father of Jack Ariola, who died last August from the rare parasite Naegleria fowleri, a flesh-eating organism that entered through his nose and attacked his brain.

His death came two years after Annie Bahneman, 7, of Stillwater, also died from an infection by the amoeba contracted from the same lake.

All three entities have moved to dismiss the case, rejecting claims in the suit that they should have issued the proper warnings of the amoeba’s potential presence in the lake and the potential for harm it posed. Washington County District Judge Susan Miles heard arguments from all sides and has 90 days to rule on the dismissal.

“Really what this case comes down to is how the court interprets the ‘recreational immunity’ statute, is that accurate?” the judge asked Pete Regnier, representing Stillwater. Under state law, government entities are immune to some extent from lawsuits resulting from injuries at recreational sites.

Regnier argued that the lawsuit is seeking to broaden the interpretation.

“This isn’t something the city could create. This isn’t something the city could contain,” he said. It would be a similar situation if someone contracted the West Nile virus from a mosquito while at a state park.

But Roger Strassburg, arguing for the boy’s family, countered that public agencies shouldn’t be allowed to hide information — in this case, knowledge of the amoeba’s presence — that would allow people to make decisions to protect themselves from harm. “That’s really the bottom line here,” he said.

Strassburg also argued that Lily Lake is essentially an artificial creation of the city, making it responsible for its safety. “This is no normal Minnesota lake; its function is part of a stormwater management system,” he said, which was the source of the amoeba. And the beach was artificially constructed for swimming.

Claims rejected

Those claims were rejected by both Jennifer Coates, an assistant attorney general representing the Health Department, and Scott Anderson, representing the city. Stormwater runs into every lake, Anderson said. “If nobody lived there, there would still be runoff.”

But Strassburg was emphatic that the hidden risks of the lake should have been made known to its users.

The day after Jack Ariola died, he noted, a sign was posted at the lake warning of the dangers. “That sign was posted by authority of the county and the city,” he said. “Their actions belie their arguments.”

At a public meeting in Stillwater in late August, a state health official said that many Minnesota lakes could have the parasite — particularly in prolonged stretches of summer heat — and it can come and go unpredictably. “It’s not something that’s quickly detectable, and it’s not something that’s going to be consistent,” Jim Koppel, deputy commissioner at the state health agency, said then.

Infections are caused when water enters the nose, enabling the one-celled organism to crawl into the brain. Most cases have occurred in Southern states, according to the Centers for Disease Control. Lily Lake’s beach was closed after Jack’s death. Health officials warned that the parasite could be found in warm water anywhere and that swimmers should not assume that closing Lily Lake meant other lakes were safe.

Jack had fallen ill and become dizzy while camping with his mother and other family members in the Grand Marais area. At first, doctors thought it was flu, and Jack returned to camp. He became sicker, with a bad headache, and a medical helicopter flew the boy from Grand Marais to Duluth, where he died. Jack was to have begun fourth grade this year at Lily Lake Elementary in Stillwater.

Annie Bahneman died from a rare form of meningitis, state health officials said. She died at Children’s Hospital in St. Paul four days after she fell sick with vomiting and a headache. Also cited in Ariola’s suit was the 2008 death of 12-year-old Hailee LaMeyer of Stacy, Minn., after swimming in Fawn Lake near her home. Her mother was also in court on Friday.