Hi there. We will be traveling with our dogs to my parents house in Northern California and I know for a fact that my moms dogs have fleas, and our dogs do not have fleas. Is it possible to use the basic flea treatments prior to heading out on our trip (i.e. as a preventative tx), and if so, how early should we start treatment? Thank you in advance. I really don't want to start a flea infestation in our home or on our dogs..