Hi,they will be planaria which are harmless,they are usually a symptom of too much food,just wipe them away and make sure no uneaten food is left in the tank,I would not use any type of medication.
yes just reduce the food,if you are worried about spooking the Discus leave the worms they wont do any harm,and will gradually reduce,every tank will have a population of these.
yeh i have them also ......like you Del i never had them before i got my discus! or is it a case of we look so close at our fish paranoide to start with that we tend to notice them ?