GASTON COUNTY, N.C. -- The Gaston County Health Department is issuing a serious warning: Be on the lookout for whooping cough.

The highly contagious bacterial illness is at a five-year high there.

Already this year, there've been 14 confirmed cases and between 15 to 20 suspected cases of whooping cough, or pertussis.

The illness is most commonly seen in elementary school-aged children. It begins with cold-like symptoms with a lingering cough that can increase in severity and last up to three weeks if left untreated.

"The coughing, sneezing, even just talking to someone can spread the disease. At the beginning stages of the disease it is very contagious," Renee Clark of the Gaston County Health Department told NewsChannel 36.

To help stop the outbreak, Clark said it's extremely important for those who suspect they may have pertussis to be seen by their doctor.

Those diagnosed are treated with antibiotics and urged to stay out of public until five days after beginning the treatment.

It's especially important for them to avoid contact with infants, small children and the elderly who can develop life threatening complications from the illness.

If you have questions about whooping cough, call the Gaston County Health Department at 704- 853-5005.