Bordetella pertussis.

Bordetella pertussis is a Gram-negative coccobacillus that is the causative agent of whooping cough or pertussis in humans. Pertussis is a highly contagious, acute respiratory illness characterized by nonproductive paroxysmal coughing episodes. Such episodes are followed by an intake of breath with a ‘whoop’ noise. Pertussis can be found in all age groups; however, most severe disease and complications are observed in infants. Despite being a vaccine-preventable disease, a recent modeling study estimates 24.1 million cases and 160 700 deaths worldwide in children under 5 years of age. The incidence of pertussis also peaks every 3–5 years. A resurgence in pertussis has been observed in the number of pertussis cases globally since 2000, with a greater incidence in adolescents. These observations may be due to genetic changes in B. pertussis, decreased vaccine efficacy, waning immunity, increased recognition and reporting of pertussis, and improved diagnostics.