Fig. 2

The relationship between apparent prevalence and sample to positive percentage (S/P%) for fasciolosis as measured by ELISA on bulk tank milk for 131 case farms (dots) and 63 control farms (triangles). Apparent prevalence is measured by dividing the total number of condemned livers by the number of slaughtered animals in 2013. The dashed line shows the cut-off value for the used commercial ELISA kit (S/P% = 30), and the solid and dotted lines show the lines of best fit for case and control farms, respectively (note that the latter group are defined as apparent prevalence of 0)