Help understanding IBD?

I understand how the disease affects boids, but my questions are like how "careful" do you have to be. Like if i bought a boa and quarantined it for 6months and then moved it into the "rack or whatever" what are the chances it would have ibd if it did not exhibit any symptoms? From what i have read boas can be carriers but not exhibit ant signs? My other Q. is how viral is it does it float from one cage across the room into another? i know you can contaminate by touching or cleaning or whatever But i am just concerned. I have a male boa i rescued like two years ago, he used to regurge alot but i think it was bacterial. The person i got him from didn't remember when the last time they fed, and was not on heat. I bred him successfully last year and he got pretty skinny after and is just starting to put his weight back on. Also I have a female *I got her from a friend like six months ago* who was acting just fine and then she started acting all weird i thought right away it was ibd but now im not sure? She was kept with a male that i have witnessed attacking a female and consticting her. I checked The *female in question and noticed her neck had a kink in it pretty close to her head. I felt it and it felt like it was separated or something didnot feel normal. Anyways she could right herself very quickly when flipped over on her back. She eats great on f/t but then i seen hr just flailing all over the place it turned out she was trying to shed. I helped her shed and she stopped immediately. It has been another month or so and she is still putting on weight and is now acting pretty normal neck looks good. These are my biggest worries if everyone can give me there input that would be great