It didn't take much explaining to them at all. They both agreed to take it! Piece of cake actually.
I reminded my son he had molluscum contagiousum as a child and that we needed to take measures to be sure that is gone and not just lurking inside somewhere, plus he is a diver and has been to lots of exotic places to dive in. He's game.
I reminded my daughter that she got some kind of parsite in China and that we ought to make sure she get rid of it in case it is lurking around also. Plus she eats raw fish in sushi. Piece of cake.
So now I'm going to order some for both of them during the no shipping costs sale and told them it's an early Christmas present.