Fluke knacker the liver, as the liver makes proteins including blood proteins there is less protein (albumin) in the blood, reduced osmotic pressure in the blood = fluid leakage into gut... slightly made that up but without resorting to google or heaven forbid opening a book that's all I've got
(scour is not always seen in flukers, probably this isn't fluke, nutritional is more likely, the best test for fluke is a blood test - its simple; low albumin the main blood protein and higher than normal globulins an inflammatory indicator = chances are fluke)
Me