Observations on the experimental pathogenicity and toxigenicity of Mortierella wolfii strains of bovine origin.

Four strains of Mortierella wolfii isolated from cattle in Britain were compared in pathogenicity and toxigenicity with a strain isolated from a cow with the mycotic abortion-pneumonia syndrome in New Zealand. All strains produced acute lethal infection in rabbits after intravenous inoculation of mycelial suspensions and all produced subacute mycotic encephalitis in mice after intracerebral injection. They also produced an acid-stable, heat- and trypsin-labile toxin in vitro. The action of the toxin was exerted mainly on the kidneys in rabbits and mice and produced effects distinct from those resulting from infection with M. wolfii.