Flying Over an HPAI H5N1 Infected Landscape 453 Table 1. Mean Area Under Curve (AUC), Cohen’s Kappa (j), and Correlation Coefﬁcient (r) of 250 Bootstrapped Autologistic Regression Models (the South and Southeast Asia Model, and the South Asia Model), when applied to all countries, India and Bangladesh, Thailand and Vietnama Model South and Southeast Asia South Asia AUC j r AUC j r All countries 0.924 ± 0.003 0.413 ± 0.005 0.620 ± 0.006 0.872 ± 0.012 0.387 ± 0.017 0.423 ± 0.012 0.916 ± 0.011 0.223 ± 0.012 0.398 ± 0.018 0.935 ± 0.009 0.382 ± 0.016 0.504 ± 0.022 0.837 ± 0.006 0.358 ± 0.014 0.578 ± 0.011 0.804 ± 0.012 0.305 ± 0.022 0.375 ± 0.012 0.861 ± 0.010 0.341 ± 0.023 0.608 ± 0.016 0.858 ± 0.011 0.536 ± 0.027 0.564 ± 0.023 India and Bangladesh Thailand and Vietnamb Thailand and Vietnamc aModels average coefﬁcients are presented in Table S1. bEstimated using HPAI H5N1 records from July 2004–2005. cEstimated using HPAI H5N1 records from 2006–present. Table 2. Mean v2 resulting from log-likelihood ratio tests applied to 250 bootstrapped autologistic regression models upon removal of each variable, presented for the South and Southeast Asia Model and for the South Asia Model, respectivelya Term dropped South and Southeast Asia Model Chicken density (Log10) Duck density (Log10) Human population density (Log10) No. of crop cycles Presence of duck farming (>20 ducks/km2) South Asia Model Chicken density (Log10) Duck density (Log10) Human population density (Log10) No. of crop cycles Presence of duck farming (>20 ducks/km2) aModels average coefﬁcients are presented in Table S2. b* signiﬁcant, *** very highly signiﬁcant, ns nonsigniﬁcant. v2 35.706 ± 9.414 50.756 ± 12.851 15.245 ± 4.252 6.760 ± 4.018 224.336 ± 33.287 18.707 ± 8.576 2.836 ± 3.025 56.829 ± 11.340 6.464 ± 4.331 56.280 ± 15.023 df 2 2 2 2 6 2 2 2 2 6 P <0.001 <0.001 <0.001 0.0341 <0.001 <0.001 0.2422 <0.001 0.0395 <0.001 Signiﬁcanceb *** *** *** * *** *** ns *** * *** April–May with several birds continuing north to Mongolia (Fig. 2a). Among the birds that had been marked, two Bar- headed Geese and one Ruddy Shelduck spent time in Bangladesh in the ‘‘hot-spot’’ (high risk) areas identiﬁed by our risk model during the timeframe when several HPAI H5N1 outbreaks in poultry were reported (Fig. 2b,c). The Ruddy Shelduck spent more than 7 weeks, be- tween February 16 and April 7, in the area predicted as highest risk for HPAI H5N1 presence by our risk model (Fig. 2c), at a distance <20 km from an HPAI H5N1 poultry outbreak reported on March 13, 2009. The migration route of two Bar-headed Geese passed near the poultry outbreak locations, but in this case, the HPAI H5N1 poultry outbreaks were reported 9 and 16 days after the birds’ presence. These three birds then undertook their northward migration toward Qinghai Lake (Fig. 2d). The Ruddy Shelduck arrived after 3 days at the Qinghai Lake region of China on April 9, 2009 (Fig. S3). The short duration of its migration in comparison to the duration of excretion reported in experimentally infected ducks (Brown et al., 2008; Latorre-Margalef et al., 2009) would allow for introduction of the virus from Bangladesh to China. A month later in May 2009, a new outbreak of HPAI H5N1 in wild birds was reported in the Qinghai Lake area of China. In comparison with the Ruddy Shelduck, the two Bar- headed Geese took a much longer period (39–50 days) to