Pertussis (Whooping Cough):

• Caused by B.pertussis and B.parapertussis
• Incubation period = 6 days
• Three stages:  Catarrhal (low-grade fever, rhinorrhea);  Paroxysmal (classic "whooping" cough);  Convalescent (resolution of symptoms over a ~2wk period)
• Full course of the disease = on average 6-8 weeks, although convalescent stage may last MONTHS
• Erythromycin may be effective early on, but no effect once in the paroxysmal stage
• Complications are most common in neonates and infants, and notably, the elderly
• Complications include apnea, hypoxia, pneumonia, encephalopathy, pneumothorax/pneumomediastinum (from paroxysms in the setting of severe mucus plugging)

References

Nelson's Essentials of Pediatrics, 5th Edition