his has to be kept in perspective the quoted article says

"....Eggs released by the adult fluke pass out of the host in it's faeces.
IF these eggs fall into fresh water, they hatch and the miracodia (larvae)
infect snails."
Now most sheep etc are dosed to prevent Liver fluke so the chances of having
infestations is very small
".... After a number of transformations, the larvae, now known as cercania,
leave the snail host and encyst on vegetation. ..." These snails are a form
of Water snail and are not the sort that would be roaming fields or your
garden...
"....These cercania excyst if infected vegetation is ingested by a suitable
mammalian host. ..."

It was always said that you should not pick WILD watercress from slow moving
water.
Commercial Watercress beds are grown in Fast flowing spring fed Streams
where there is NO POSSIBLE chance of Animal ingression.

British Watercress is a hell of a lot safer than most of the Imported Salad
crops on sale in your local supermarket, which can carry up to 10 times the
level of chemicals that are allowed in British grown crops.

--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk