It only takes one (1) pill from the vet to get rid of them. So it's an easy fix. They come from the pup eating and digesting an infected flea. So be sure to treat your yard or keep her from wherever you think she picked them up. The flea has to be infected and then ingested, so be sure to check her real good for fleas also. It does not come from flea bites and it does not pass to humans, so you're safe and your baby will be fine.