Table 3. Variables significantly associated with highly pathogenic avian influenza (HPAI) H5N1 occurrences in wild birds reported by the linear and quadratic logistic regression analyses using 1000 bootstrapping training datasets. All values in the table are mean values obtained from 1000 runs of the model. Italics indicate quadratic effects. Variables marked in bold were included in the final model.

Linear and quadratic logistic regressions Moran's I VIF (all) Stepwise selections
Variable OR 95% CI OR †   P value Pseudo R2 AIC AUC ± SD Kappa ± SD VIF (selected) Times P value 95% upper CI ‡
DEM 0.989 0.984 0.995 <0.001 0.09 784 0.65 0.02 0.3 0.04 0.08 11.65 3.73 856 0.013 0.044
Slope 0.8 0.728 0.88 <0.001 0.06 798 0.61 0.02 0.17 0.04 0.13 5.29 3.5 803 0.029 0.099
Aspect 0.998 0.997 0.999 0.007 0.03 810 0.58 0.02 0.14 0.04 0.12 1.23 1.09 295 0.048 0.142
MpreJan 0.984 0.976 0.991 <0.001 0.05 803 0.55 0.02 0.18 0.03 0.25 46.02 2.95 993 0.002 0.025
MpreFeb 0.983 0.974 0.992 0.005 0.04 817 0.54 0.02 0.15 0.03 0.26 42.08 -
MpreMar 0.985 0.976 0.995 0.029 0.03 813 0.53 0.02 0.14 0.03 0.31 32.31 -
MpreApr 0.985 0.974 0.996 0.046 0.02 816 0.59 0.02 0.21 0.04 0.21 11.37 -
MpreOct 0.989 0.982 0.997 0.036 0.02 815 0.54 0.02 0.13 0.04 0.27 13.73 2.58 148 0.072 0.171
MpreNov 0.99 0.983 0.997 0.035 0.02 815 0.52 0.02 0.14 0.03 0.24 23.79 -
MpreDec 0.985 0.979 0.992 0.001 0.04 804 0.55 0.02 0.15 0.03 0.21 47.98 -
TminJan 1.013 1.008 1.018 <0.001 0.08 788 0.63 0.02 0.36 0.03 0.36 467 7.55
TminJan 1.027 1.019 1.035 <0.001 0.23 714 0.71 0.02 0.38 0.04 818 0.017 0.050
TminJan2 0.407 0.318 0.522 <0.001 601 0.026 0.099
TminFeb 1.013 1.008 1.017 <0.001 0.07 791 0.61 0.02 0.35 0.03 0.49 524.7 -
TminFeb 1.026 1.018 1.034 <0.001 0.22 719 0.69 0.02 0.37 0.04
TminFeb2 0.406 0.314 0.525 <0.001
TminMar 1.016 1.01 1.022 <0.001 0.07 790 0.62 0.02 0.35 0.03 0.46 363.9 -
TminMar 1.033 1.023 1.043 <0.001 0.21 725 0.66 0.02 0.36 0.04
TminMar2 0.441 0.347 0.561 <0.001
TminApr 1.013 1.006 1.021 0.012 0.03 810 0.57 0.02 0.21 0.03 0.31 228 -
TminApr 1.022 1.012 1.032 <0.001 0.06 797 0.56 0.02 0.22 0.03
TminApr2 0.758 0.652 0.881 0.005
TminMay 1.011 1.004 1.019 0.034 0.02 815 0.55 0.02 0.15 0.03 0.32 295.2 -
TminJun 1.014 1.007 1.022 0.006 0.04 809 0.58 0.02 0.17 0.03 0.31 355.3 -
TminJun 1.022 1.012 1.033 <0.001 0.05 803 0.57 0.02 0.18 0.03
TminJun2 0.818 0.703 0.952 0.041
TminJul 1.013 1.006 1.02 0.01 0.03 810 0.59 0.02 0.19 0.04 0.27 359.6 -
TminJul 1.023 1.013 1.033 <0.001 0.06 801 0.58 0.02 0.2 0.04
TminJul2 0.799 0.69 0.926 0.019
TminAug 1.015 1.008 1.022 0.002 0.04 805 0.62 0.02 0.27 0.04 0.26 543.9 -
TminAug 1.031 1.019 1.042 <0.001 0.08 788 0.62 0.02 0.27 0.04
TminAug2 0.739 0.636 0.859 0.002
TminSep 1.018 1.011 1.025 <0.001 0.07 795 0.66 0.02 0.33 0.04 0.25 272.8 -
TminSep 1.04 1.029 1.052 <0.001 0.14 760 0.66 0.02 0.33 0.04
TminSep2 0.657 0.567 0.76 <0.001
TminOct 1.019 1.013 1.026 <0.001 0.08 789 0.67 0.02 0.32 0.04 0.27 156.17 -
TminOct 1.04 1.029 1.05 <0.001 0.16 750 0.67 0.02 0.5 0.04
TminOct2 0.649 0.563 0.748 <0.001
TminNov 1.016 1.01 1.022 <0.001 0.07 795 0.64 0.02 0.34 0.03 0.34 143.6 -
TminNov 1.034 1.024 1.043 <0.001 0.16 752 0.65 0.02 0.47 0.33
TminNov2 0.624 0.533 0.73 <0.001
TminDec 1.008 1.003 1.012 0.013 0.03 811 0.59 0.02 0.34 0.03 0.42 340.5 -
TminDec 1.022 1.015 1.029 <0.001 0.16 750 0.62 0.02 0.35 0.03
TminDec2 0.506 0.415 0.616 <0.001
TmaxJan 1.008 1.004 1.013 0.004 0.04 807 0.59 0.03 0.36 0.03 0.46 713.2 -
TmaxJan 1.022 1.015 1.029 <0.001 0.2 729 0.66 0.02 0.39 0.04
TmaxJan2 0.42 0.333 0.531 <0.001
TmaxFeb 1.008 1.004 1.012 0.003 0.04 807 0.58 0.02 0.34 0.03 0.53 594.4 -
TmaxFeb 1.019 1.013 1.025 <0.001 0.19 737 0.64 0.02 0.36 0.04
TmaxFeb2 0.437 0.348 0.55 <0.001
TmaxMar 1.009 1.005 1.013 0.004 0.04 808 0.58 0.02 0.28 0.03 0.47 182.5 3.47
TmaxMar 1.016 1.01 1.022 <0.001 0.16 753 0.64 0.02 0.3 0.03 867 0.015 0.069
TmaxMar2 0.456 0.36 0.577 <0.001 860 0.016 0.066
TmaxOct 1.007 1.002 1.012 0.05 0.02 816 0.56 0.02 0.24 0.03 0.46 141.7 -
TmaxOct 1.005 1 1.009 <0.001 0.08 788 0.58 0.02 0.25 0.03
TmaxOct2 0.638 0.534 0.763 <0.001
TmaxNov 1.008 1.003 1.012 0.017 0.03 813 0.58 0.03 0.31 0.02 0.44 262.4 -
TmaxNov 1.02 1.013 1.026 <0.001 0.14 763 0.61 0.02 0.32 0.03
TmaxNov2 0.549 0.455 0.663 <0.001
TmaxDec 1.008 1.003 1.012 0.013 0.03 812 0.58 0.03 0.34 0.03 0.43 376.3 -
TmaxDec 1.022 1.015 1.029 <0.001 0.16 750 0.62 0.02 0.35 0.03
TmaxDec2 0.508 0.417 0.619 <0.001
NDVIJan 82.131 14.274 477.48 <0.001 0.15 754 0.69 0.02 0.3 0.04 0.36 161.5
NDVIJan2 0.415 0.324 0.533 <0.001
NDVIFeb 8.325 2.2 31.558 0.047 0.02 816 0.57 0.02 0.21 0.04 0.3 361 -
NDVIFeb 79.637 13.711 468.14 <0.001 0.15 756 0.68 0.02 0.29 0.04
NDVIFeb2 0.428 0.335 0.548 <0.001
NDVIMar 13.368 2.92 61.357 0.03 0.02 814 0.57 0.02 0.2 0.04 0.28 87.07 2.41
NDVIMar 111.333 15.489 811.8 0.001 0.14 760 0.66 0.02 0.27 0.04 997 0.001 0.014
NDVIMar2 0.445 0.348 0.57 <0.001 1000 <0.001 0.003
NDVIJun 0.03 0.004 0.263 0.008 0.06 798 0.62 0.02 0.21 0.04 0.24 79.06 -
NDVIJun2 0.668 0.563 0.793 <0.001
NDVIJul 0.006 0.001 0.046 <0.001 0.11 775 0.64 0.02 0.26 0.04 0.26 183.2 3.56 672 0.038 0.125
NDVIJul2 0.533 0.436 0.652 <0.001 805 0.029 0.100
NDVIAgu 0.015 0.002 0.113 <0.001 0.09 787 0.62 0.02 0.24 0.03 0.22 101.13 -
NDVIAgu2 0.572 0.467 0.701 <0.001
NDVINov 23.449 4.637 119.04 0.014 0.03 812 0.58 0.02 0.19 0.04 0.43 142.5 -
NDVINov 15.49 2.708 89.102 0.048 0.05 803 0.62 0.02 0.22 0.04
NDVINov2 0.759 0.628 0.919 0.036
NDVIDec 30.448 6.566 141.736 0.004 0.04 807 0.59 0.02 0.22 0.04 0.45 99.86 3.26 980 0.005 0.037
NDVIDec 28.187 5.417 147.905 0.008 0.07 797 0.64 0.02 0.25 0.04
NDVIDec2 0.72 0.591 0.877 0.016

† Calculated using z-score standardized variables to avoid too small or too large OR values
‡ All p values of 95% lower CI are less than 0.001