A 14-year-old Minnesota boy who was believed to have died from an infection linked to a rare, brain swelling amoeba died instead from a bacterial infection, state health officials said Monday.

Testing by the federal Centers for Disease Control confirmed that Hunter Boutain had a case of streptococcal meningoencephalitis, the Minnesota Department of Health said in a statement.

The department in early July reported it was investigating whether Hunter had contracted primary amebic meningoencephalitis after apparently being exposed to the freshwater amoeba Naegleria fowleri after swimming in Lake Minnewaska near Alexandria, Minn.

News of the death and its apparent connection to the parasite gripped water-friendly Minnesota. State and national health officials scrambled to determine whether the state was becoming a more hospitable place for the deadly water amoeba that typically poses a greater risk to swimmers in southern states.

Two other children had died of the infection since 2010, but this case puzzled state health officials because it occurred in a much bigger lake that had not been subject to a recent heat wave.

The laboratory results "help bring clarity to the situation, but do not lessen the tragic nature of this case," the department said, adding that there is always a "very low-level risk of infection with Naegleria fowleri when swimming in fresh water."