Saw a flea on an 18 day stay dog. What do I do?

I'd advise Yes, you must ask the owners, otherwise if a dog is already treated, adding any more chemical solution could have toxic serious medical consequences. Even a dog that is give a preventative for dogs can pick up a flea hitchhiker. If the dog is already on preventative, the best course of action is to brush/comb all dogs after each walk, looking carefully for any more signs and wash all soft items that can be laundered in hot soapy water (bedding, etc). It's worth mentioning that asking about what the dog gets as far as medical preventatives before booking a stay is a good idea, in case these type of situations occur.

I know this pet has already gone home but (for the future) in case you are in this situation again. I normally will give them a pill called "Capstar" it is an over the counter product that you can pick up from your veterinary office. (and yes it is over the counter so you do not need an exam) Capstar is an oral pill that the pet takes. It starts killing fleas within 30 minutes and is out of the pets system in 24 hours. They cost about $5 a pill (give or take a little bit) so not too bad o cost wise. As far as telling the owners, that is a must. I actually will bring this up during the meet and greet. When going over the details of their pets stay one of the questions is what flea medication do they use for their pets, and if they give it monthly. Many times, O will say that their pets don't have fleas. Which in turn is a great time to remind them that they will be around other dogs, going on walks, ect. ways that they can get fleas. and will mention the capstar pill to them. This helps not only their pets out should I notice a flea but also helps me out so if one dog has fleas I will give everyone a pill so they don't go home with fleas. All my clients are told upfront of my concern with fleas and the measures I take to make sure that all the pets go home flea free, and so far (knock on wood) the few times I have had to give some dogs a capstar pill the owners have been understanding and appreciative . But being upfront with them and making sure that they know is a must. Take care!