A young Texas girl is fighting for her life after she was infected with a deadly brain-eating amoeba following a day spent swimming in a river, according to reports.

Lily Mae Avant, 10, went swimming over Labor Day weekend in the Brazos River near Waco — where doctors believe she contracted the often-fatal Naegleria fowleri amoeba, news station KWTX-TV reported.

Days after her swim, the Valley Mills Elementary School student started experiencing a fever and a headache, according to the station.

Though she appeared to be suffering from symptoms of a common virus, her family said they still believed that “something was not quite right,” according to a Facebook page launched to support Lily.

Then one night, Lily’s mother heard concerning noises coming from her daughter’s room.

“She was incoherent, unresponsive and was quickly swept up and taken to the ER,” the page said.

Lily was then flown to Cook Children’s Heath Care System in Forth Worth, where a spinal tap revealed she had contracted Naegleriasis, a rare infection caused by the amoeba.

The amoeba — which is found naturally in freshwater — isn’t life-threatening when accidentally swallowed but can be fatal if it enters the body through the nose, according to the Centers for Disease Control and Prevention.

“It’s every parent’s worst nightmare,” her aunt, Crystal Warren, told KWTX. “For this to happen to her when there were so many other people in the same waters on the same days we just don’t understand why it was her.”