Skip,
That is very interesting but it contradicts what I have understood completely.

"... (IBD) is believed to be caused by a retrovirus. This disease is usually passed from snake to snake by mites, but it can be spread through contact. Inclusion Body disease can be contracted by boas and pythons. It is always fatal. In pythons IBD quickly progresses to infect the brain and typically results in death within two to four months. In boas, the disease tends to infect all the organs of the body before reaching the endgame brain infection, so infected boas may live more than two years without showing symptoms."

Barker and Barker, BALL PYTHONS: History, Natural History, Care & Breeding 2006

I have a second reference here someplace I'll post it as soon as I can locate it. I am not discounting what you say at all, but I have understood that boas and pythons respond differently to this disease. I don't believe it is common as everyone wants it to be as according to the information I had kills quickly and requires direct contact (like pet stores often have)