Fig. 3.

Three-dimensional sex-specific contour maps (a.k.a. risk surfaces) for ZIKV seroprevalence as a function of estimated BSA and age. The underlying GAM was adjusted for an SES proxy, hours without water, and location of the water faucet. Combinations of age and BSA that synergistically increased or decreased the conditional probability of ZIKV infection would appear as quadratic peaks or troughs on the 3D risk surface, respectively. No such quadratic peaks were observed in any population. The contour maps for females and males in the pediatric group were nearly planar (A and B). In the household group, ZIKV seroprevalence increased linearly with BSA for both females and males, conditional on age (C and D).