Both dogs have diarrhea... ??

Hey everyone. My 8 year old Basset Hound had a bad case of diarrhea this week. Acted pretty normal besides being extra "clingy." She had very frequent stools that composed of mostly mucous. I decided to take her to the vet Friday. I was unable to collect a sample beforehand b/c the last time she went was in the house and at that point I didn't think I was going to take her to the vet. Anyway, the vet tried to obtain a sample and couldn't because she was empty. He prescribed 10 doses of flagyl (over 5 days) and doggy kaopectate for her. After 1 day of flagyl and kaopectate she has improved tremendously. No more diarrhea and is acting like her old self again... Last stool was formed.

Unfortunately this morning my other dog started having loose stool. No mucous yet, just very runny. I've been watching them both like hawks to make sure they haven't gotten into anything. No table scraps either. Is it possible that my puppy caught the diarrhea from my basset hound? I gave him some kaopectate but no flagyl.

Should I give my pup a few doses of flagyl or just let my Basset take the whole 5 days?

I just didn't think dogs passed diarrhea back and forth....

Any advice would be greatly appreciated..

Laurie