So just how common and how contagious IS IBD?

[Skiploder]

That is really fascinating information, but how was it determined that he was really dealing with OPMV? The way you described IBD makes it sound like some kind of autoimmune disease, so is it possible that the IBD made the snakes more susceptible to OPMV? I read that OPMV is much more common in venomous snakes, but I'm not sure how common it is in boids compared to IBD.

Once the vet figured out that animals without IBD were also getting sick he did what good vets should do - he started looking at other diseases. OPMV is confirmed via HI testing. God only knows what some of the vets we read about on this forum would do in such a situation............

Ask a dedicated exotics vet what they see more off - OPMV or IBD. Do not ask this of a casual vet or a vet who thinks everything can be treated by jabbing an animal with baytril - ask a REAL exotics vet. IBD may be very common in some species, but it may not be as lethal as we think. Many animals can be asymptomatic indefinitely.

In the case of Don's collection, snakes with IBD and snakes without IBD were affected indiscriminately.