The presence of the heat-stable neurotoxin in the pertussis cells.
D000818:Animals; D001886:Bordetella pertussis / Q000032:analysis* / Q000166:cytology; D004673:Encephalomyelitis, Acute Disseminated / Q000209:etiology; D006168:Guinea Pigs; D006358:Hot Temperature; D007114:Immunization; D009498:Neurotoxins / Q000032:analysis*
D009498:Neurotoxins