Has your dog ever been treated for giardia?

Her stool is jelly like substance and smelly. Does this sound like giardia to anyone who's dog has had it? The stool sample will be tested tomorrow for confirmation. In the meantime, she's on metronidazole (just started tonight) and had rice for dinner. We're stumped as to how she would have gotten it. If your dog has had it, did you have any ideas how he/she got it? Our pit mix is 11 months old and hasn't been near any other dogs that have had it. One of the woman I work with is treating her dog for it, but our dogs never come in contact. We're in separate buildings on the premises. The only thing that I can think of is that I tracked from her office to mine, but I thought infection only occured when they drank out of the same water dish or were exposed to the stool of an infected dog. Any ideas/advice before we hit the vet tomorrow? I'm just an overly worried mom...