For the country-level analysis, we compared the predicted reporting dates with the actual reporting dates, for countries where the disease arrived by May 8 th , 2009 ( Figure 3 , Supplemental Online Figure S1 ). We validated the model by determining how well a model fit to data up until May 8th predicted reporting dates for fourteen countries where the disease was detected between May 9 th and May 19 th (Supplemental Online Figure S2 ). The correlation between forward predicted and observed dates was 0.62, and the observed reporting date fell within the 95% confidence interval for all countries. Many of the actual reporting dates are earlier than predicted, which is expected due to the nonlinear nature a of log-log survival analysis regression. In particular, countries that had not reported disease by the cut-off date were included in the analysis by designating these as locations that ''survived'' the entire study period without acquiring the disease (i.e, censoring). This appropriately extends the predicted reporting dates by including information on both countries that had reported disease by the cut-off date as well as countries that had not. Using this methodology, we also estimated the reporting date of the disease in the remaining 103 countries and the 95% confidence intervals ranged from April 17 th to May 29 th , 2009 (Supplemental Online Figure S3 ).