Cloned lines of Babesia bovis differ in their ability to induce cerebral babesiosis in cattle

Clones of a Babesia bovis isolate known to cause particularly severe cerebr al babesiosis were tested for virulence phenotype by inoculation of cattle. Clones were selected for phenotyping by two criteria - rate of growth in c ulture and hybridization of a virulence-related probe to Southern blots. La rgely on the basis of associated mortality, B. bovis clones were judged to vary in their pathogenic potential.