Pertussis, a respiratory illness commonly known as whooping cough, is a very contagious disease only found in humans. It is spread from person to person. People with pertussis usually spread the disease to another person by coughing or sneezing or when spending a lot of time near one another where you share breathing space.
Many babies who get pertussis are infected by older siblings, parents, or caregivers who might not even know they have the disease. Pertussis is a serious disease that can cause babies to stop breathing.