POWAY, Calif. -- A 14-year-old Poway High School student has been diagnosed with whooping cough, a highly contagious disease that causes severe coughing, county health officials announced Tuesday.

The student is the 29th person in San Diego County this year to come down with the illness also known as pertussis, which causes patients to cough with a distinctive whoop sound, according to the county Health and Human Services Agency.

Patients also might suffer from flu-like symptoms and vomiting. The incubation period is normally 7-10 days, but could range up to 21 days.

The HHSA reported that the infected student was not immunized against the disease.

"It's extremely important for parents to ensure that they and their children are protected against vaccine-preventable diseases including whooping cough," said county Public Health Officer Dr. Wilma Wooten.

The doctor said whooping cough could cause severe complications in infants, including pneumonia, brain damage and death.

School officials have informed parents about the risk of exposure to the illness through letters and e-mails, according to the HHSA.