Ryan,
TMV is my greatest fear in growing tomatoes and other nightshade plants. Here in NC it is a major threat as we are on 'tobacco road'.
I only grow TMV resistant strains of tomatoes but who knows how vulnerable our superhots are.
Here is a pretty good article from our NC State Univ. Agro site..... http://www.ces.ncsu....dnotes/vg15.htm
Good luck with your fight!
Curious to know if any of the people in the shared garden are smokers.
If your own plants aren't affected and you didn't handle theirs, obviously you're not the source.
And yes, use of tobacco products can transmit the disease.
It'd be tough to track down the source and more difficult still to eradicate.
Pretty much have to slash and burn and have a scorched earth policy.
That or nuke them from space.
Good luck on those plants.