ABSTRACT
Eosinophilia; a pronounced increase of eosinophils in the blood or tissues; occurs in numerous important circumstances; like allergic diseases; parasitic infections; and cancer. Helminthic parasites are usually the common parasitic infections witch cause eosinophilia apart from two enteric protozoans; Isospora belli and Dientamoeba fragilis. Infection with helminthes parasites produces immune effector responses and in a reaction to various stimuli; eosinophils are recruited from the circulation into inflammatory foci; where they modulate immune responses via sequences of mechanisms. The defence against organisms that are too large to be phagocytosed; particularly parasitic helminthes seems to be the primary role of eosinophils. In this article; we will discuss some of the biological features of eosinophils and their role in parasitic infections