A health alert for North Texas as a student at Lake Dallas High School in Denton County has been diagnosed with pertussis, commonly referred to as whooping cough.

Denton County Public Health Department sent a letter to parents asking them to make sure their student’s immunizations are up to date as the bacteria is highly contagious and can spread quickly in a school setting.

On the heels of the announcement, a Dallas emergency room doctor is reminding the public, while this is not a widespread issue, families need to be vigilant.

"I don't want to strike too much panic in the public here… this is not the bubonic plague. But this is a significant illness," said Dr. Scott Jones of Trusted ER Hillcrest. "There are people who die from it."

Dr. Jones said the best form of defense is vaccination, to be followed up by booster shots.

"We're seeing more and more of it [whooping cough]. In the 1980's, we kind of thought we had it leveled off. But since the 1980's, cases have been slowly growing by the year. Back in 2012, we had a peak year since 1955. So we are heading the wrong direction," said Dr. Jones.

Dr. Jones said the most vulnerable are children, specifically infants, older adults and people who have pre-existing, respiratory conditions.

"It's sneaky because the initial symptoms look and sound like a regular cold. You get congestion, maybe a runny nose and some sneezing, low grade fever and a little tearing in the eye perhaps. That will last for a few weeks and then this is where the coughing comes in and the breathing issues come in," said Dr. Jones.

Dr. Jones said if you have questions about your immunization status or your child's, the best place to start is your family's general practitioner.