That is the 64000 $ question Dan
Many people do breed them and hope that as the overt features of the
disease (namely the ulcers) are in remission then it is likely that the
fish's immune system is in control and holding the infection at that time
and hopefully the eggs and fry will be OK.
The only way to test is to subject the fry to stress (e.g. overcrowding and
not enough water changes etc) and see if they break out.
I have seen references that Mycobacteriosis (TB) can be transferred through
eggs.
Cheers
Bruce