I have never, ever quarantined shrimp (freshwater). I don't believe they carry things the same way fish do. I'd be interested to hear an expert opinion on this though.
I never bothered qt shrimp. They are pretty frail and fragile and I figure they would b dead if they were sick. I also cant load them up on meds in QT so I figure its pointless. Shrimp in your sump is brilliant though. Ive been recommending it for years