A student at a high school in Loudoun County, Va., died last week after contracting the flu, her mother said.

Katie Giovanniello, 16, a sophomore at Heritage High School in the Leesburg area, died at a hospital Friday morning, said her mother, Colette Giovanniello.

The county health director and a spokesman for the county school system both confirmed the death but gave no cause.

On Tuesday, the Virginia Department of Health reported what it said was the “state’s first influenza-associated pediatric death” for this flu season. It said a Northern Virginia teenager, who was between 13 and 17, “has died from complications associated with influenza.”

The department did not name the teenager and said that for privacy reasons, it would provide no additional information about the death.

On average, three flu-related pediatric deaths are reported each year in Virginia, the health department said.

Colette Giovanniello said her daughter saw a doctor on Feb. 2 and received a flu diagnosis. She was taken to a hospital on Thursday as her condition deteriorated, Giovanniello said.

Her daughter had no known underlying health problems or conditions, Giovanniello said.

“She was such a very, very popular” student who was “well loved by everybody,” her mother said. She was just a “really, really nice girl. People loved her.”

Virginia health officials said so far this season, 773 flu- and pneumonia-related deaths had been reported in the state through Feb. 1.