[Systemic blood diseases in inbred mouse strain CC57W]

In "low cancer" CC57W mouse line studied over a period of 1944--1969 spontaneous leukemias occurred in 0.4--6.8%. During 1971--1976 the frequency of spontaneous leukemias amounted to 33%. Morbid anatomic and hematologic studies showed that aleukemic and subleukemic forms of chronic generalized reticulosarcomatosis with predominant affection of the lymphatic system accounted for the overwhelming majority of systemic diseases of the blood. Electron microscopy revealed virus-like type C particles in the cells of the affected organs.