CCD is a combination of matters that the EHB has not yet built an immunity system too.
With what was already bothering the Bees along with stress, add a new strain or a combination of things they have never coped with and you have it.
Too many areas have been affected to point to one location and one cause.
Does anyone know if the Africanized bee has a better defense system other than aggressiveness???
Which will not ward off disease, only things that may carry it. :)doak