Isolation of Myxosoma cerebralis (Whirling Disease) Spores from Infected Fish by use of a Physical Separation Technique

Immiscible, liquid, two-phase systems are produced when aqueous solutions of dextran and of polyethylene glycol are mixed above certain concentrations. This phase system was used to isolate Myxosoma cerebralis spores from infected fish tissue. Myxosoma cerebralis partitioned into the polyethylene-glycol-rich upper phase, whereas the tissue debris partitioned into the dextran-rich lower phase. Myxosoma cerebralis spores partitioned into the upper phase, regardless of the electrostatic potential in the phase system, indicating that isolation of M. cerebralis was unrelated to surface charge, which suggests that relative to fish tissue, the surface of the spore is highly hydrophobic. The technique is useful for detection of small numbers of spores from populations of infected fish; however, the greatest value of the technique is the isolation of spores for biochemical and immunologic studies that are unmodified by the relatively harsh techniques usually used.Key words: Myxosoma cerebralis spores, Myxosoma spore isolation techniques, polymer aqueous two-phase systems