Model M was parametrized to describe epidemic spread only in Castiglione di Cervia and Castiglione di Ravenna. Daily estimates of the number of vectors over time N v were obtained by the vector dynamics model. The ratio of mosquitoes to humans was estimated to be in the range of 10-35 during the peak mosquito activity (Fig. S3 show the predicted dynamics of the vector for different numbers of breeding sites B). By fitting model M to notification data up to August 23 (the day before intervention) and by assuming B = 200 ha {1 we estimated k to be 0.09 days {1 (95% CI 0.05-0.16 days {1 , see Fig. 4b ). We recall that the explored range for k through the LHS procedure was ½0,1. Good fit to data were obtained for values in the entire range explored for all the other model parameters (see Fig. S4 ). x h Human susceptibility to infections 50%-80% [58] p s Symptomatic ratio 82% [18] p n Notification ratio 54% [18] 1=v v Latent period in mosquitoes 2-3 days [26, 58] x v Mosquito susceptibility to infections 70%-100% [62] doi:10.1371/journal.pone.0018860.t003 The uncertainty of k depends on the uncertainty of all model parameters. Unfortunately, no field data are available for the study area to validate these results. In [37] , plausible values for the biting rate and the ratio of mosquitoes to humans in Europe are considered to be k~0:25 days {1 and N v =N h~2 0 (based on published and non published data, e.g. [10] ). However, we acknowledge that it might be misleading to compare these results with others carried out in other localities. In fact, abundance and biting rate of Aedes Albopictus are strongly affected by abiotic factors, both climatic and environmental (e.g. presence of other hosts).