Experimental observations on the eosinopenia induced by acute infection.

The effect of trichinosis on the number of eosinophils in the peripheral circulation and in the marrow has been determined in mice by accurate techniques. There is a sharp rise in number of eosinophils in the bone marrow and in the peripheral blood beginning about the 10th day, which persists for some weeks. The correlation between peripheral blood and evidence of bone marrow production is remarkably close. When acute Escherichia coli pyelonephritis is induced during the height of eosinophilia due to trichinosis these cells rapidly disappear from peripheral blood and bone marrow, so that by the end of 24-48 hr the counts are in or near the normal range.