Two weeks ago I treated Ginger with advantage (as per the vets instructions) and it doesn't seem to have helped. I've noticed that she's still biting and I saw a small black bug on her face yesterday. I tried to get it, but it crawled back under her fur. I know that advantage is a monthly treatment so I can't treat her for another two weeks. Is there something else I can do so that her kittens don't get fleas when they are born?