Comparison of the virulence of various strains of Moraxella bovis.

The relative virulence of various strains of Moraxella bovis (M. bovis) was studied using the eyes of mice and cattle. The investigation consisted of three separate experiments. Experiments I and II involved a study on the effects of (1) different methods of growth and (2) serial blood agar passaging on the virulence of M. bovis. Experiment III involved a study on the relative virulence of different strains of M. bovis and M. bovis-like organisms. Strains of M. bovis and M. bovis-like organisms varied in their pathogenicity for mice. However, different methods for preparation of exposure cultures of M. bovis did not influence the disease produced.