An acute, highly fatal epizootic disease of cats is described, which can be recognized by a fulminating and extreme leucopenia involving all types of white blood cells, aplasia of the bone marrow, including both the granulocytic and the erythrocytic series and occasionally the megakaryocytes, aplasia of lymphoid tissue, and characteristic intranuclear inclusion bodies in the cells of the intestinal mucosa and in certain cells of the spleen, lymph nodes and bone marrow.
The infection has been induced in healthy cats by means of bacteria-free filtrates of emulsions of the spleen of infected animals. Collateral evidence supports the conclusion that the disease is due to a virus. The pathogenicity of the infectious agent has proved thus far to be strictly limited to the natural host.
