The U.S. Centers for Disease Control and Prevention conducted confirmatory clinical testing for the organism Naegleria fowleri, and on Monday reported the results to the Minnesota Department of Health.
Naegleria fowleri has been confirmed as the cause of the rare illness that claimed the life of 9-year-old Jack Ariola Erenberg earlier this month.
MDH officials said the cause of the illness had been 99 percent certain before, but the CDC test results made it 100 percent certain.
They said while it will never be possible to know for sure where the child was infected, the timing of the illness and other factors point to Lily Lake in Washington County.
Jack Erenberg had been a student at the Rush City elementary school last year.