Its a viral infection, so yes, it possibly can be transferred. That being said, I had a purple tang with a bad case of it and none of my other fish ever caught it, even though the purple tang would frequently rub up against the yellow tang.
Lymph generally pops up in fish that are immunocompromised - either from stress or other disease processes. So, make sure your parameters are all good and try to eliminate any other sources of stress on the fish.
Good thing is that it usually clears up on its own, just keep on top of your water quality, and provide good nutritious foods.
--Christy