Variations in the buoyant density of foot-and-mouth disease virus strains.

Some of the factors which effect the buoyant density in caesium chloride of foot-and-mouth disease virus were investigated. Under standard conditions, the buoyant densities of a range of vaccine virus strains, representing all seven serotypes, were found to be unrelated to their potential of being formulated into effective vaccines. In some virus strains, a small amount of naturally occurring high and/or low density components were observed and these components were examined in more detail in one virus strain.