Bordetella pertussis is a Gram-negative, aerobic, pathogenic, encapsulated coccobacillus bacterium of the genus Bordetella, and the causative agent of pertussis or whooping cough. Its virulence factors include pertussis toxin, adenylate cyclase toxin, filamentous haemagglutinin, pertactin, fimbria, and tracheal cytotoxin.