IDENTIFICATION OF INTRACELLULAR STAGES OF CYCLOSPORA SPECIES BY LIGHT-MICROSCOPY OF THICK SECTIONS USING HEMATOXYLIN

Cyclospora sp is a recently identified coccidia responsible for enteri c infection in humans. Most reports have failed to detect this parasit e in intestinal biopsies by light microscopy, although the different s tages have been ultrastructurally described in jejunum enterocytes. Ve ry recently, some investigators have reported the detection by light m icroscopy of parasitophorous vacuoles in intestinal biopsies; however, only transmission electron microscopy (TEM) could clearly identify th e parasitic stages, To improve the histological diagnosis without usin g TEM, we have tested different staining methods in biopsies obtained from a patient infected by the human immunodeficiency virus who was sh edding Cyclospora oocysts, Hematoxylin stain alone for 15 minutes on 5 mu m-thick sections of duodenal biopsies was found to be the most eff icient method for observing different stages of the parasite. In parti cular, the banana-shaped merozoites were visualized and appeared very similar to the human coccidia Isopora belli. This simple technique may be useful in diagnosing Cyclospora infection. Copyright (C) 1996 by W .B. Saunders Company