The mother and grandmother of a toddler who died in December face criminal charges for allegedly neglecting his severe diaper rash, leading to a fatal infection.

Amy Livingston (search), 27, of Johnstown, was charged Tuesday with involuntary manslaughter and child endangerment in the Dec. 12 death of her 15-month-old son, Harley. She was charged with a second count of child endangerment because another son, 3-year-old Hunter, also had severe diaper rash, authorities said.

Her mother, Evelyn Ann Mrsnik (search), 60, was charged with child endangerment, because she was a supervisor at a day care center Harley attended. Mrsnik had an obligation under state law to report the alleged neglect, District Attorney David Tulowitzki said.

The younger boy developed sepsis (search), a life-threatening infection, because the rash was so bad, Cambria County Coroner Dennis Kwiatkowski said.

"It's probably the worst I've ever seen," Kwiatkowski said.

Mrsnik didn't immediately return a message left at her home Tuesday night. It was not immediately clear whether she or her daughter have attorneys. The Associated Press could not immediately locate a home telephone number for Livingston.

Both defendants face a preliminary hearing March 17. Involuntary manslaughter involving a victim under 12 carries a sentence of up to 10 years.

Livingston's husband, David, was deployed by the Army when the boy died, authorities said.