Partial dependence plot of factors with positive effects: total population, mean MIR, temperature 4 weeks before WNV cases are reported, and January temperature.

The central black line is the partial dependence line, which is the average marginal effect of each factor on the WNV cases. The green shade around it is the standard deviation of the individual conditional expectation (ICE) lines, which is the predicted marginal effect by each sample of each factor on the WNV cases. The blue shades are samples from the ICE lines, showing the range of predicted marginal effects by each individual sample. The MIR and the weekly temperatures in 1–4 weeks before also have similar trends as the mean MIR and the temperature of the current week.