Chris,
Accepting that it is the adult bees that carry and infect the next
generation of brood.
Consequently, this allows for the possibility of passing the infection
from one hive to another by transferring adult bees.
But are you stating that if brood comb is transferred from one colony to
another - this will not spread the disease?
Once the larvae are dead - then are they considered as non -infectious
bodies?
Ref. taken from JD and BD Yates "Beekeeping study notes (modules 1,2,3
and 4) suggest that it is the fecal material from larvae that do not die
that allows the spread via. house bees. What about fecal material from
larvae that do die - is this infectious?

What is really wanted is a good description of the life cycle and
infective periods of M. pluton - at least by this beekeeper!
Any references that you know of?
Peter