Schistosomiasis, enterobiasis and amebiasis are endemic parasitic infestations in Egypt, that were condemned by many
authors as having a role in the pathogenesis of appendicitis. In the present work 127 appendices removed from patients
suffering from symptoms and signs of appendicitis in the emergency surgical unit in Theodore Bilharz Research Institute
(TBRI), Egypt, during the period of time from 6/96 to 6/99. Gross and microscopic histopathological examinations were done for all cases in the pathology department (TBRI). Females were found to be more affected than males with most of patients were at the second decade of life. Parasites were detected in 14.8% of removed appendices. Enterobius vermicularis worms were detected in 10% of cases having no or mild histopathological changes, in 5.3% of cases with histopathological picture of acute appendicitis and in 14.3% of cases with histopathological features of chronic appendicitis. Schistosomiasis infestation was detected in 6.3% of removed appendectomy specimens and in 28.6% cases with histopathological features of chronic appendicitis. Amebiasis was not detected in any of the examined appendices. We concluded that infestations of the appendix by schistosomiasis and enterobiasis are important factors in the pathogenesis of appendicitis in Egypt, thus early and proper diagnosis as well as treatment of these infestations is indicated to avoid the development of appendicitis with subsequent appendectomy.