Wilson was transported to Lakeland Regional Medical Center for symptoms of apparent carbon monoxide poisoning.
Crews opened the windows to the home and found Terryn Wilson, 7, dead in a bed after it was safe to enter the home.
A neighboring duplex had dangerous levels of carbon monoxide, as well.
No one else was affected.
"This is the first death our agency has worked related to Hurricane Irma. It's a tragedy when anyone dies, but when a child dies, it's a horrific tragedy. Please, please follow safety instructions that we have stressed over and over so no other tragedies such as this one occur," said Sheriff Grady Judd.