Figure 3A: Map of the probability of WNV focal area without mosquito abatement areas.. The probability of a tract being in a WNV cluster is based on logistic regression. The human case point locations are provided for reference. The equation for this model is Y = -10.607 + (2.732 * LK_PLAIN) + (.034 * PCT_WHITE) + (.085 * MED_AGE) + (.020* PCT_HOUSES50-59) + (.0001 * MED_INC) - (.278 * HOUSE_KMSQ) - (.0001 * DIST_BIRD). Figure 3B: Map of the probability of WNV focal area with mosquito abatement areas. The outlines of the mosquito abatement areas are considered approximate and are drawn from the best information available at the time of writing. The area marked as "Chicago" indicates that area for which the City of Chicago oversaw the mosquito activities during 2002. This is not to be considered the metropolitan outlines of the city. The equation for this model is: Y = -6.575 + (4.025 * NSH_MAD) + (.049 * PCT_WHITE) + (2.387 * SCK_MAD) + (1.201 * LK_PLAIN) - (.114 * ELEV_RANGE) - (.0001 * DIST_BIRD).