Bob:
Hopefully whatever it is will stay contained within the new snake population and not spread to the other snakes in your collection. So far that's what happened with mine.
Have you spoken to Doc Walker about this yet? You're getting good advice from everyone here but with the limited access you have to a reptile vet it may be more productive if Doc checks the snakes on his end. You said he's a great guy so I'm sure he'll take whatever steps necessary to rectify your situation and to contain the problem before it spreads any further, if a problem is found. He did refund my money for the ones that died.
One thing - when my snakes died I threw away anything they came in contact with, on the advice of the very knowledgable people here. That included tubs, water bowls, deli cups, etc.
Good luck to you.