Definition:

Pertussis, or whooping cough, caused by the gram-negative bacillus Bordetella pertussis, is a highly contagious, acute respiratory disease of humans. Despite high vaccination rates, this illness has re-emerged worldwide, causing approximately 300 000 deaths each year. Waning immunity after childhood immunization has resulted in a growing pool of susceptible adolescents and adults who are capable of transmitting pertussis to vulnerable unvaccinated or incompletely vaccinated infants. The hallmark symptoms of pertussis are paroxysmal coughing with whooping and post-tussive vomiting. Persistent coughing may last for weeks to months with a gradual decrease in frequency and severity. However, it should be noted that B. pertussis infections, particularly in hosts with partial immunity to the bacterium, may also follow a much milder or subclinical course. Complications that are frequently associated with classical pertussis include pneumonia, otitis media, seizures, encephalopathy, and (brain) hemorrhages.