You've had the leopard frogs in with them since last summer 2014? And you've had the tree frogs together 5 years? If the WTFs and AGTFs have been together that long then I don't see any reason to separate those at this point, but there are diseases which have been known to take months to complete a life cycle and then just "show up out of the blue" (still researching parasitology) and wipe out an entire collection...
I believe a similar scenario was posted on FF from a WTF keeper with that exact same scenario. He had introduced a new, apparantly healthy female to his long time collection, and months later he lost his entire collection of WTFs he'd had for years
