I'm not a vet and don't have much experience with worms, but does this necessarily mean they need deworming?Mina had posted photos of stools dense will live worms. I expect safe deworming was advisable in this case.
I remember the last time I had pinworms, it didn't start with a few worms every now and then. Suddenly my stool was full of them, very similar to Minas picture (it was horrible ).
The amount decreased from day to day and after two or three weeks I saw no worms anymore, for many years now.
I guess I must have had them for a long time already until my body finally decided to get rid of them? In that case it would have been too late for medication, I wouldn't have needed it anymore.