small potatoes- crop rotation question

[mopinko]

do potatoes build up the same sort of viral load as tomatoes if grown in the same spot year after year?
last year i planted a lot of fingerlings. used the straw method. since they are small to begin w, and the ones that did the best were the purples, lots of itty bitty ones got left behind.
they came up this spring, and did pretty well for me. just covered them up with a new load of straw. but again, i am sure when i dug them that i left plenty behind.

should i let them grow this spring, or should i pull them and move them somewhere else? if i can leave them, how many years can they stay in the same place?
long term i am focused on permaculture, and the idea of a self perpetuating potato patch is appealing.