The three 8 week old kittens I am fostering through a rescue have fleas. They have been in my home for 32 hours now and the kittens and my own pets received prevention right away when I noticed them at 20 hours after being in my home. I also applied flea powder on all of my carpets. The kittens have been confined to one room; after I noticed the fleas, they have been confined to a kennel on a tarp in the same room. All linens have been washed. One kitten slept on me, on a blanket, on the couch last night. My animals, who haven't interacted with them, don't have any signs of fleas. Should I be concerned about the fleas having spread through my home? Please put my mind at ease! Are there any additional steps I should take? Fleas are so gross, they make me so nervous. Thank you.