(A) Human eosinophils isolated from peripheral blood by negative selection (B) Eosinophilic infiltrates in the intestinal wall of an Owl monkey, A. trivirgatus (image courtesy of Dr. Alfonso Gozalo, Comparative Medicine Branch, NIAID) (C) Eosinophils in mouse bone marrow cytospin. Eosinophils can be found in all mammalian species, and are easily recognized by their large, prominently stained cytoplasmic granules. Panels (A) and (C) reprinted with permission from reference [36].