I have two assissin snails in my fish tank. I always wondered if these snails have lungworms in them. If they do, what should do to prevent contracting the lungworm.
No. Go lookup the life-cycle of the rat lungworm. It and most other parasitic organisms have very specific stages and vectors for being transmitted, in this case the rat lungworm is specifically carried through a land based snail and slug lifecycle, using rats as a carrier for one of those stages.
With that being said, I still wouldn't eat snails or anything out of a freshwater home or other closed-system warm water aquarium. There's plenty of potential pathogens such as amoeba and nematodes that could easily exist in a home aquarium.