It doesn't seem to me to be a virus on your banana. Maybe some nitrogen and magnesium deficiency.
Beside that I suspect something else which is more possible.
You see most of the banana plants in US are propagated by tissue culture. The propagator to maximize profit is re culturing the small plants many times and with this comes a drawback: mutations.
To me your banana seems to be variegated by accidental mutation which is okay and presumably safe to eat just like all the monsanto corn.
PS: I have namwa as well, and have seen them in their habitat in thailand.