Question

2- after add a substrate that allows color to be detected in positive samples. Intensity of color is correlated with intensity of infection. What would be your conclusion if 50% of the cattle you tested came up positive? (do we know if all 50% are actively infected?!)

Answer 1

Assuming that aseptic conditions are followed during the procedure and the samples are not contaminated, the 50% test samples with the positive test results need to be considered infected. This is because the color intensity indicates the severity of an infection. Otherwise chances for the false positive results must be considered.