If all the live suspect material is gone, there would be no need to remove any soil. This would include any bulblets you may have missed, or broken scales from the bulb left in the soil that may produce new plants that would still be infected.
edited to add
There are some nematodes that live in the soil that can transmit virus. Zone 4, and maybe zone 5, areas need not worry as these nematodes do not survive the winters.
