SEATTLE - A 7-year-old girl from Kent has apparently died at home on Monday from a heart condition aggravated by the flu. 

The King County Medical Examiner says Sarah Horner died from myocarditis, an inflammation of the heart caused by viral infections like the flu. 

Horner was a second grader at Kent's Lake Youngs Elementary School  The school principal was forced to send a painful letter home to parents explaining that the flu affected Sarah's heart, causing her death. 

"It's a particularly heavy time for this school," said Becky Hanks, Kent School District spokesperson. "She was well-liked.  She was a little second grade girl and kids in her class were really fond of her." 

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Sarah Horner was a second grader at Lake Youngs Elementary School in Kent, Wash.

Dana Tate has twins at the school. One of them was in the same class as Sarah. 

"We were devastated," said Tate.  "They were scared.  They were concerned, but they're working through it." 

Health officials stress Sarah's death was the result of a rare reaction to the flu and there's no evidence the flu is causing serious problems in other children. In fact, she's the first child to die in King County from the flu since 1999. 

"It was not contagious," said Hanks.  "It's really important for people to know that." 

Neither Lake Youngs or any other Kent school is experiencing an unusual number of flu cases right now.  But that's not the case at Seattle's Bishop Blanchet High School.  Bishop Blanchet is keeping its doors closed for the rest of the week in an effort to control the spread of the flu. 

Nearly one in three Blanchet students stayed home from school Wednesday. 

"There were nine people missing in my German class," said Brian Thomas, student. 

"One of my classes I had 8 people in it," said George Dotis, student.  

The hope is that giving students a few days away and giving the school a good scrub-down will help this student body defeat this year's flu. 

Although there are concentrated pockets of flu cases, health officials say the number of cases statewide is still relatively normal. Since flu season can hang on until the spring, they say it's not too late to get some protection with a flu shot.

The Associated Press contributed to this report.