I'm thinking of growing a serious quantity of watercress in my garden.

We have a small river running at the bottom of it that I plan to
utilise. I don't actually mean growing it in the river, because I'm
concerned about liver fluke infestation as it flows through sheep
pasture a short way upstream, but using the water from it.

The thing is that, despite a lot of searching, I'm not sure how liver
fluke is transmitted via watercress - ie is it taken up by the plants or
do the flukes somehow attach themselves to it? If it is the latter,
would some kind of filtering remove them?

Anyone here know about this?