ELISA MAP results of all samples collected in the study. Plasma samples were evaluated with the ParaCheck (Prionics USA Inc., La Vista, NE; formerly CSL/Biocor) ELISA. In this figure the optical density value as measured at the end of the ELISA process is shown. Although a cut-off is defined for each batch of samples, the approximate cut-off value for samples to be considered MAP positive is a value greater than 0.20 optical density units. Overall prevalence of positive samples is approximately 1.4%.