several questions about tapeworms

I am a cat foster Mom so have had a few kitties come through recently. 

5 months ago I had a cat, and soon noticed she had tapeworms, and treated her. She had no recurrent symptoms. 

Now, I have two new kitties, they've been with me for two weeks, and only NOW i noticed a good crop of little tapeworm segments on the bed and a few on the fur near one of their booties. 

3 questions:

1- could there have been eggs laying around from 5 months ago that these guys ate and got infected with?? (I vacuumed everything, including couch etc)

2- how often do you see segments come out? Am I horrible for "missing" these signs earlier? Or are the segments only released occasionally?

3- my boyfriend is imposing a "no cats on the bed until they are worm-free" rule- how long after tx until worms are killed? They're getting the praziquantel (droncit) and flea treatment this morning. 

Thanks a lot everyone!!!

Barnaby is helping me write this very post...

 

I don't know the answer to any of your questions, but I'm guessing the answer to the first one is no.

Tapeworms come from cats eating fleas, so is it possible these kitties came in contact with a flea or two?

Anyway, I'm guessing your Vet could answer all your questions.  Did you happen to ask them while you were there getting them de-wormed? 

Thanks Mrs Green Jeans!

I was looking up more stuff online, it said eggs might live up to 3 mos! Wow! but out of the window for my timing. 

The group that I foster thru, Cat Town, just gave me the oral de-worming medicine they use at the shelter, (and the cats fell for the pill pocket) and topical flea treatment, so I didnt have to take them in to the vet. 

They may have been in contact with fleas right before they came to me, for sure. I guess the life cycle of the little worms is in this time frame...

THanks for your repl!!

From what I've read, it takes 2-3 weeks from the time an animal swallows a flea with tapeworm larva in it, to the worm maturing enough to start shedding segments for the owner to see. Given the timing my guess is this started just before you got your cats.