Few problems with fleas these days. If I find or suspect them, bathe her with mixture of dial soap, vinegar, and water. 1 part of each of first two to four parts water. Seems to do the trick, repeated in a few days on one occasion. One or two fleas washed away.Wash her blankets.
In the old days, one "flea bombed" the house. Took people and pets (Dogs for baths) out and set them off in the house. Used to work, but haven't heard of that recently. Someone suggested spraying apple cider vinegar on the dog and let it sit for 5 to 10 minutes before bathing the dog. There seemed to be a lot more flea episodes in those days. I had two dogs, but no explanation.
My pup became very lethargic and dull on Seresto-recovered day after I removed the Seresto. Others rave about the collars. She is seldom around other dogs or their hang outs. But still fleas are in the greenery in our neighborhood, I am sure. She sleeps in our room so I bathe her about every ten days routinely.