Figure 2. . . Epidemiologic linkage in 6 patients infected with Bordetella holmesii during pertussis outbreak, Japan, 2011. Duration of illness for each patient is shown as a gray box. Patient 3 provided unreliable information about the date of onset and recovery, but the patient’s cough lasted for >1 month. Epidemiologic linkage was observed between 5 patients (patients 2–6), but not for patient 1.