Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts
Figure 4.(a) National historical and projected WNND cases.

Interannual variation in human WNND cases (filled circle, solid line) and deaths (open circle, dashed line) in the USA and projections of WNND cases under mean current (MC), extreme current (EC—95th percentile) mean future (MF) or extreme future (EF) conditions. Error bars include both the standard error of the mean projected values and the standard deviation of the residuals between current projected and actual values. (b) Summed totals of current maximum number of yearly cases and projected future cases with and without immunity in states where immunity was (grey) or was not (black) significant.
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