Updated

Health officials have closed Lily Lake to swimmers until further notice while the Minnesota Department of Health investigates the death of a boy who appears to have died from a rare form of meningitis caused by an amoeba found in warm freshwater, myfoxtwincities.com reported.

Officials suspect 9-year-old Jack Ariola was killed by primary amebic meningoencephalitis, also known as PAM; however, they are still waiting confirmation from the Centers for Disease Control and Prevention. He was taken off life support  Tuesday.

The boy's father, Jim Ariola of Wyoming, Minn., told the St. Paul Pioneer Press his son swam in Lily Lake early to mid-last week, where he frequently swam with his sisters. Ariola says his son was traveling with his mother in Grand Marais when the infection took hold Friday.

"He didn't -- he didn't know who I was," Jim Ariola said.

Ariola said his son loved hockey and wrestling. He was getting ready to start fourth grade in Stillwater this fall, and was set to start a hockey clinic on Wednesday night.

More On This...

PAM is caused by an organism known as Naegleria fowleri, a microscopic amoeba that is commonly found in warm freshwater and soil across the world. It infects humans by entering through the nose -- usually while swimming or diving, and it causes a severe brain infection that is nearly always fatal.

Officials stress that infections are very rare. In fact, the last known case of PAM in Minnesota was reported in August 2010 after a 7-year-old girl named Annie Bahneman died from the same brain infection after swimming in Lily Lake.

"The risk of infection from Naegleria in Minnesota is very low," said Richard Danila, assistant state epidemiologist, in a statement. "We do not want to discourage people from swimming. Rather, simply avoid swimming, diving or other activities in obviously stagnant water while temperatures are high and water levels are low."

PAM infections, while extremely rare, usually occur in warm, southern states. Between 2001 and 2011, 40 cases were reported in the United States.

Click for more from myfoxtwincities.com.