If you have dogs and they have fleas, do the fleas stay on the dogs rather then jumping off? I do not have a dog but my sister came by with hers and now I have fleas. She claims that there are no fleas in her home and she never gets bitten but we have been under attack. I checked two of her dogs and found on one the black droppings of the fleas. I am concerned even if she comes over that there could be fleas on her as well and she will re-infect my home, can that happen as well.