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The district asked families to be vigilant in ensuring students with influenza-like illness be kept at home to avoid spreading illness in school.
Some North Texas doctors fear this could be another record breaking year for pertussis.
Pertussis is a common childhood illness. In infants, the bacteria creates a toxin which affects the hearts and lungs and can be deadly. There is a vaccine for children, but in spite of that, there were a record-breaking 286 cases in Tarrant County last year.
"That outbreak has continued into this year, and we're actually on track for having a record year for pertussis in Tarrant County," says Dr. Mark Shelton, of Cook Children's Medical Center.
Shelton said one reason is because more and more adults are getting the illness and passing it on to children.
He recommends adults get a TDAP booster which contains pertussis protection, so they don't pass it on to their children.