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FESTUS, Mo. – A Jefferson County school district has an outbreak of whooping cough. So far, more than a dozen cases have been reported.

Pertussis or whooping cough began to appear at the Festus High School and Intermediate School around mid-October. Health officials say whooping cough is a serious bacterial illness.

District officials say 59 students have reported symptoms: 15 have tested positive for whooping cough, while 22 tested negative, and 22 were waiting for results. Fourteen of the students attend the high school and one student at the intermediate school.

Symptoms for the virus include coughing, runny nose, sneezing, and possibly a fever.

The best way to prevent spreading pertussis is by covering your mouth when you cough or sneeze and to wash your hands.

The district was asked if unvaccinated students were the cause of the outbreak. The district says that’s not the case. Less than half a percent of the student population is unvaccinated. None of those who tested positive for pertussis displayed symptoms.