Degree Name

Master of Science (MS)

Semester of Degree Completion


Thesis Director

Bill T. Ridgeway


On January 1, 1973, 10 soil samples were collected from areas in Coles County, Illinois, in an effort to isolate soil amoebae. All 10 soil samples were cultured on bacto-nutrient agar and colonies of amoebae genera isolated were Acanthamoeba and Hartmannella. Amoebabacteria cultures prepared from soil isolates were injected into each of 10 adult mice which were sacrificed at the end of the nine days and examined for evidence of infection and pathogenicity. Lesions were observed in two mice and amoebae cysts and bacterial colonies were present in nine mice. Amoeba-bacteria cultures were purified using streptomycin antibiotic discs and the bacteria-free amoeba cultures were injected into each of 10 adult mice. After seven days the mice were sacrificed. No lesions were observed. However, microscopic examination of the liver, spleen, kidney, small intestine and brain revealed the presence of amoeba cysts in all the mice. Appropriate controls were used. Results suggest that local free-living soil amoebae could adapt to parasitism and may be potentially pathogenic. No deaths were recorded from the amoebae although some mice appeared moribund during the incubation period. Acanthamoeba was present in a wider range of soil samples and appeared more infective to mice than Hartmannella.