Fig. 5

Proposed cluster areas in Shandong Province, 2005–2015. The time period was investigated for control phase (2005–2009) and elimination phase (2010–2015). A Indigenous case in 2005–2009 containing a–c, B imported case in 2005–2009 containing d–h, C indigenous case in 2010–2015 containing i and j, and D imported case in 2010–2015 containing k–m. The cluster analysis was performed with the default maximum spatial cluster size of <50% of the population