FIG. 3.

Detection of WNV IgM in sera of experimentally infected rhesus monkeys by using the Drosophila-expressed WNV prME antigen. Individual serum samples were diluted 1:336 and tested in the WNV EIA. Each diluted sample was assayed twice on consecutive days, and mean absorbance values were calculated. The dashed line represents the provisional cutoff value of 4.20 determined from testing of human volunteer donors (Fig. 2).