Ive also cleaned a lot of these without colour run problems, but on this one it has occurred due to flooding.
The obvious answer as Mike knows knows is to use bleach, however as the absorbancy is high on these rugs its important not to let the bleach wick up the pile where it meets the fringe. Probably a bit of a drawn out job, applying bleach and rinsing off shortly afterwards, followed by further applications until an acceptable level is reached.
Dave.