There is a live vaccine which comes in a neat little applicator bottle with a couple of sharp blades which nick the skin as you apply a drop of vaccine. A scab forms at the site, but because the vaccine is live, the scab is infectious, so you have to be very careful when and where you vaccinate. Experiments on the virus in Edinburgh have shown that it is almost impossible to kill in the environment, being well able to survive exposure to Scottish winters.
The only saving grace is that it is only spread through direct contact with a cut or skin abrasion - so if lambs get it, the ewes' teats will also be infected. If sheep with scabs on their mouths are feeding from a trough or bucket, scabs will drop off and be picked up by another sheep. This only matters if they have some skin damage to the mouth - hence our problem with our prickly field.
Being a virus, there is no cure, just antibiotics to guard against secondary infection, and wait for the natural antibodies to build up and defeat it - about 4 to 5 weeks. The pics on the FWi page are fairly extreme - we have never had anything as bad as that. Just a few scabs round the mouth and maybe on the top of the head if ram lambs have been fighting. We find that in our bad field, normally grazing meat lambs, if one gets it, maybe 30% will, but as it seems to only be quite a mild strain, the ones affected will have had a little set back, but it's all over in a few weeks.