Body weight and body temperature of JCL: ICR mice infected with Sendai virus decreased depending on the viral dose. In severely infected mice, there were significantly higher values of hemoglobin, hematocrit, red and white blood cell counts, and leucin aminopeptidase (LAP), and lower values of reticulocytes and lactic dehydrogenase (LDH) . The other values tested were comparable to those of the non-infected mice.