A comparison of six methods for the concentration of a porcine enterovirus.

Single-step concentration of porcine enterovirus strain T80 by adsorption to the polyelectrolyte PE60 gave virus concentration factors of 35- to 88-fold in terms of plaque-forming units, with recovery rates of 22 to 75% of total virus present in the original virus suspension. Concentration by separation in an aqueous polymer two-phase system gave virus concentration factors of 56- to 105-fold and recovery rates of 37 to 107%. In the latter procedure, sodium dextran sulfate appeared to have no effect on plaque numbers, although plaques were sharper and clearer when this substance was incorporated in the overlay. The failure of sonication of virus concentrated by either procedure to increase plaque numbers indicated the absence of virus aggregates in the concentrates. T80 virus was not effectively concentrated by cobalt chloride or polyethylene glycol precipitation or by adsorption to either aluminium hydroxide or calcium hydrogen phosphate.