The way I understood it IBD spreads with direct contact with infected snakes, bad hygiene or mites. I have never seen an actual case of IBD and thought it very unlikely I would ever seen one. Unfortunately I was recently told by a large scale breeder that his vet believes that about 35- 40% of the CB Boa population carries the virus in it's dormant state and most won't ever show signs but Pythons die very quickly from it. I'm not one to spread fear but that is the reason why I only buy boas from established names and reputable breeders.This is one reason most people keep their boas and pythons in separate rooms or even separate floors or buildings, or decided not to breed boas at all. You can get your boas tested at a vet for peace of mind.