Unfortunately it only takes 1 flea to create an infestation. And the problem with Flea eggs is that they are not sticky, so they will drop off and sit anywhere. Also a flea larva develops into a pupa and can remain in that state for up to two years. And it only takes one to survive and hatch and you get an infestation again.

There's a useful free information site on pet fleas, their lifecycle and how to get rid of them here Got Fleas? : Fleas Life Cycle there's lot's of info on what to do - Got Fleas? : Flea Treatment - unfortunately you will have to be vigilant and keep on killing them - Got Fleas? : Killing Fleas ... I guess you may only have 2 years to go...

I wish there was better news, or a real quick fix!

Best of Luck

Michelle