Sounds like tapeworm to me too. I've seen them--as wiggly rice grains--a few times. One time I found them the day after the second of two poop tests (we did a fecal and an SAF) came back negative. I have doubts about routine fecals, but we did find whip in one screening test.
As Batmom said, tapeworm is easily treated with Droncit. My vet prescribes two doses: one immediate, one a month later.
It's definitely not an e-vet situation. Take a sample of the infested poop to your vet so they can confirm the type of worm, and, if tapeworm, the source (flea or animal).