Not to me, but you might find an answer in one of the radio interviews he's given. They are archived, and there are links at his web site.
I tend to think that like many bugs, Marburg has changed, or this is a different branch of the Marburg family we've never seen before.
For instance, Ebola has several different strains, one of which is airborne but does not cause disease in humans, although it's fatal to monkeys. Ebola Reston, I think it is.
Thanks for the ping. Just pray that this monster bug burns itself out.
My first thought is that the hospitalized patients were the ones who were already desparately ill and that others recovered at home, creating an artificially apparent high death rate. By the time patients got to the hospital they were already at death's door.
I suspect something similar with Bird Flu.