The Minnesota Department of Health is investigating a case of a child who came down with a severe brain infection after swimming in Lake Minnewaska in Pope County.
The department said in a news release Tuesday that the child had recently been swimming in the lake, and became "critically ill" shortly afterward with a likely case of primary amebic meningoencephalitis (PAM).
Officials haven't released any other information about the child at this point.
The PAM infection, which the department describes as "very rare and severe," is caused by a microscopic amoeba called Naegleria fowleri, which is commonly found in fresh water and soil around the world.
Infection only occurs when the organism enters a person's body through the nose – usually when people get water in their nose while swimming or diving – and then travels to the brain, according to the health department. It is nearly always fatal.
Naegleria thrive in warm water, so infections are more common in southern states. The number of people who become ill is relatively low, with 35 cases reported across the country from 2005-2014, the health department notes.
But two children in Minnesota died of PAM in recent years – a 7-year-old girl in 2010 and a 9-year-old boy in 2012. Both of them became infected while swimming at Lily Lake near Stillwater.
PAM is also suspected, but unconfirmed, as the cause of death for two other children, according to the St. Paul Pioneer Press.
The health department said people who swim in fresh water can reduce their risk of infection by keeping their heads out of the water, or holding their noses shut or using nose clips.
James Ariola, the father of the boy who died after swimming in Lily Lake, sued the city of Stillwater, Washington County and the state Health Department in 2013, saying those agencies should have warned the public about the dangers of swimming in the lake after the first child died in 2010.
The Minnesota Supreme Court dismissed Ariola's lawsuit in January, according to KSTP.
Officials didn't close the beach until after Ariola's son, Jack Ariola Erenberg, died in 2012. It has not been reopened.
Lake Minnewaska is a popular destination for anglers and boaters in west-central Minnesota. It's located in central Pope County between the towns of Glenwood and Starbuck.
Municipal swimming beaches are located in Glenwood and Starbuck, and they remain open to the public, according to MPR News.
The Minnesota Health Department has more information about Naegleria and PAM on its website.