The article reports the detection of the mast cells count by means of acridin orange stain in the suckling mice infected with EHFV. The results showed that the mast cells in the subcutaneous fascia proliferated obviously.The everagenumber of the mast cells undereach 50 high power field(mc/50H)of those animal infected by EHFV A9Smp14,A3Smp7 and L99Smp7 wererespectively 372.72,275.53 and 620.37 corpusle,while the control groups were 36.5,25.8 and 59.14 corpusle, The figures of the experimental grous were ten times higher than of the controls(P
