Have u ever fed live? If so where did u get the feeder from? Did u get the snake from a breeder? (Same feeder questions about breeder) if so then the source has to be put out so others can be aware and so the breeder can check his animals. I'm not an infectious disease expert but I don't think a parasite can be frozen, ingested and reproduce. Maybe. It prolly came from when it got loose. Hopefully ur vet will help narrow it down. Sorry to hear it. Good luck