Why shouldn't you let a dog lick your hands when it has worms?

So, apparently my dog's been indulging in some delicious fox faeces that had worms in it -- I never knew this until this morning when I saw a big piece of paper with 'DOG HAS WORMS, wash your hands after touching him!' written on it. However! Last night I was drunk and letting him lick my hands in blissful ignorance, and probably ate a Scotch egg or two afterwards. Am I going to be giving birth, as it were? Not that I mind my own little worm babies, but you know, pro-choice isn't always bad.