Subject characteristics*.

Subjects were classified into four disease phenotypes including West Nile encephalitis/paralysis (WNE/P), West Nile fever/meningitis (WNF/M), asymptomatic disease, and random blood donors (RBD). The RBD controls were only genotyped for the 3 significant SNPs.*The two study subjects for whom disease severity is unknown are not presented. CCR5 genotyping was performed on a subset of the samples presented here. Please refer to the Methods for a description of the CCR5 sample sizes in each WNV category.aself-reported ancestry.bclinical outcome categories are not mutually exclusive.NA, not applicable.