Table 3. Model of occurrence of WND cases in humans in administrative districts of the European Union between 2002 and 2014, according to the predicted structural bird-borne risk of WNV circulation and to the population size.

Variable	Odds-ratio (95% confidence interval)	p-value
Intercept	0.008 (0.004–0.016)	<0.0001
Proportion of pixels classified high-risk with a probability >0.5a	1.7b (1.5–1.9)	<0.0001
Proportion of pixels classified high-risk with a probability >0.8 a	7.4b (2.9–24.0)	0.0001
Population size (x105)
<1.3	Ref.
1.3–2.5	1.5 (0.7–3.4)	0.34
2.5–4.8	3.5 (1.8–7.5)	0.0006
>4.8	3.1 (1.5–6.5)	0.002

^aPixels with an predicted risk above the 90^th percentile of the risk distribution in >50% (resp. 80%) of bootstrapped risk maps.

^bOdds-ratios computed for an increase of 0.05 of the proportion.