EFFECT OF INOCULATION OF VEGETATIVE MYXAMOEBAE OF CELLULAR SLIME MOLDS (ACRASIEAE) IN MICE, RATS, AND GUINEA PIGS

Abstract

Intracerebral injection of vegetative myxamoebae of strains of Polysphondylium pallidum caused 80 to 100% mortality in mice, whereas a 30 to 50% mortality occurred with strains of Dictyostelium giganteum and D. mucoroides. Death is attributable to an unidentified toxic factor. Histopathologically a giant cell formation was seen in the spleen of mice. This cell was different from Langerhan's or foreign body giant cell. Rats injected intracerebrally behaved similarly. Intranasal instillation of myxamoebae in guinea pigs caused transient pneumonia. Myxamoebae do not multiply in the brain tissues of mice or rats, or in the lungs of guinea pigs.
Intranasal instillation of vegetative myxamoebae is less pathogenic than free living amoebae like Hartmanella culbertsoni, H. rhysodes, Naegleria sp. (Culbertson strain HB-1), or Naegleria aerobia.