Figure 2. Speed or log speed (km/d) of Zika introduction into municipalities in Brazil. A) June 2015–May 2016; B) January 2015–May 2016; C) January 2015–May 2016. Municipalities are classified by region. Gray circles indicate central–western region, green circles indicate northern region, light blue circles indicate northeastern region, black circles indicate southern region, and dark blue circles indicate southeastern region.