Last week that number jumped to 42-percent.
In Fresno County 10-percent of the entire student population is believed to be sick with the flu.
That is more than 19-thousand kids.
A nurse from Fresno Unified said, they are seeing a surge.
But schools especially with little children are taking precaution.
Singing and holding hands fills this classroom with a lot of joy.
But it's that kind of physical contact that makes classrooms a perfect breeding ground for the flu.
Catherine Mathis is constantly surrounded by the children at Fresno State's early education center.
She said every time this year Flu cases increase.
Catherine Mathis: "Once in a while, we'll have days where we'll have usually this time of year one teacher out per class room or two teachers out in a class room which rarely happens."
Hand washing is Mathis' number one tool against a miserable bug.
So far her classes have escaped widespread illnesses this year.
Fresno Unified Nurse Gail Williams says students in her district aren't so fortunate.
Gail Williams: "With the kids, we're not as clear on numbers right now. But we are seeing a spike with kids with fever, cough, and sore throat."
Fresno County Health Officials confirm what schools are experiencing.
But it is not a statewide problem yet.
David Luchini, Fresno Co. Dept. of Health: "Northern California has a lot of flu activity while Southern California hasn't been as busy as Northern California with flu activity. If Southern California starts picking up then I think there's chance we get into widespread classification."
Health officials ask if your child is showing the slightest signs of the flu, please don't bring him or her to school.
Fresno Unified is also reporting flu problems among school nurses.
In the past two weeks five-percent of their nursing staff has called in sick.