Officials with the Weatherford Independent School District confirmed Heather Holland's death.
The district said the 38-year-old died early Sunday, reported WTVT in Dallas.
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"She was a very, very kind lady, very good teacher. Everybody thought very highly of her, so it's really tough," said parent Lindsay Larossa.
Larossa had seen Holland just last week when their kids played together.
The district says the school where Holland taught has not seen an unusual amount of flu cases this season.
The school was on a rotating cleaning schedule with other schools and had just been deep cleaned on Friday.
School officials contacted the families of Holland's students directly to tell them about her death. The rest of the school was notified in a letter.
Counselors are expected to be on campus all week.
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