FIG. 3.

The proportionality of ELISA readings was determined for one culture-positive T. truncatus (white triangles) and four culture-positive S. coeruleoalba serum samples. Serum samples were diluted and tested by ELISA until the optical density did not vary significantly and numbers approached background values of six RBT negative serum samples obtained from resident healthy animals (two S. bredanensis, three T. truncatus, and one S. coeruleoalba). (A) Optical density iELISA readings. The standard deviation at all points was less than 5%. (B) gELISA optical density readings. The standard deviation at all points was less than 5%. (C) cELISA optical density readings. The standard deviation at all points was less than 5%.