I have never specified a particular disease. I think that might limit your folding ability in a race but don't quote me.....................
Edit: I looked at the project summary list don't see any pattern to how they assign cores and work units based on the disease. If anyone else knows different please chime in.
Also, if you don't have a passkey, get one. And start crunching so you can get 10 WUs done before the race starts.