i have two cats in my house. they never go outside. i had fleas in my house in november. bathed, dusted, cleaned,washed everything and think they were gone. now it is august and they are back. where are they coming from? my house is about a 30 year old ranch with no basement. the yard has mature trees and a dry ravine behind it. how can i prevent this from happening again? should i treat outside the house? this has never happened to me previous at other houses/apartments.

Fleas can be tough to get rid of. It is possible that you are unintentionally bringing the fleas in from the outside, or that a few fleas managed to survive the clean-up in November and the population has now reached a large enough size that you're noticing the cats scratching. The University of Kentucky has a nice info. sheet that should help you decide where the fleas are coming from and how to best get rid of them. http://www.ca.uky.edu/entomology/entfacts/ef602.asp Good luck!