> I would add that the indiscriminate use of Terramycin also masks the
> symptoms of AFB, allowing it to be spread via spores in the scales in
combs.

I'm not sure what 'indiscriminate' means here, but I think it has been
proven in practice and is currently being proven in research that judicious
use of OTC prevents outbreaks of AFB (with all the associated massive
sporulation and contamination of comb), and that, over time, in the absence
of outbreaks, natural background spore levels in hives drop to the point
where subsequent breakdowns become increasingly unlikely.

allen
http://www.internode.net/honeybee/diary/