Whooping cough cases have tripled in Colorado. Be aware of the symptoms.

According to the CDC, Infants ages 1 and under are at greatest risk for serious disease and death because their immune systems are still developing. Also, whooping cough isn't always easy to identify at first.

"You'll have a normal cold like a runny nose, a little bit of a cough, a little bit of a fever, and then you think you're fine. But, then a week or two later, after those symptoms, then the coughs begin," said Dr. Malcolm Anderson. Pediatric ICU Physician from Rocky Mountain Hospital for Children.

Watch the CBS News Colorado story

Get additional information about the pediatric ICU