M.M.
Do you have a pier and beam foundation? I had fleas in college b/c of the pier and beam foundation. I had to fog under the house, as well the inside. I don't use foggers now, I use fumigators - it doesn't leave a film and gets in the cracks much better. We had a huge infestation 3 summers ago (we had 4 dogs, an acre w/ possums, rabbits and armadillos) - the fumigators wiped them out w/ one application.