Parasites would have made her sick, but not killed her so quickly without symptoms. IBD would have manifested with symptoms before the death. Boas are native carriers of the IBD virus, so they can hang on longer once symptoms begin. You would have seen stargazing, anorexia, body contortions, and a loss of strength and coordination before she passed.
An infection could possibly kill her in that time frame, as well as lead to the regurgitation and the intense pain that might prompt her to bite herself.
So I guess my first guess would be an infection, and it sounds like an infection of the ovaducts might be a good guess. But I would still get your other snake checked out.