US workers have demonstrated that Batrachochytrium dendrobatidis is a pathogen of crayfish as well as frogs and other amphibans. They have demonstrated it in quite high proportions (<29%) and they can carry it for at least 12 wks.
As yet only a limited range of species have been examined. But this is especially concerning as crayfish have been moved around the world for aquaculture and of course may walk away from where they have been put. This potentially spreads the organism easily.
see McMahon, T.A et al. PNAS January 2, 2013 vol. 110 no. 1 210-215