I feel for you.
When we first rescused Annabelle she had a tape worm...and yes it looked like little peices of moving rice...GROSS.
Gracie and Lizzie never got them though, thank God.
The Vet told me to make certain that she didn't use the same litter box as the other girls...which was fairly easy for me since I don't work outside the home.
But if you do, maybe just keep her in a room by herself until you get her to the Vet.
On a side note, if I had it to do over again I'd have opted for the shot to take care of them right off the bat...no, not me I tried the pills first and they just didn't seem to work...I took her back and the Vet gave her a shot and within a day at the most the worms were gone.
Good luck, I know what a pain it is!