الملخص

Objective: to investigate the occurrence of cryptosporidium oocyst in patients with malignant disease before and after receiving chemotherapy.Methods: A follow up study of 107 patients before and after 2-3 months from receiving chemotherapy compared with 100 healthy subjects studied as a control.Results: 1. The study revealed a significant increase of cryptosporidium oocyst (18.37%) in patients after receiving chemotheropy in comparison with (8.39%) in patients before receiving chemotherapy and (5%) in control group.2. In our study we used lodine stain with simple modification by using the oil immersion power for the diagnosis and in this case we obtained excellent diagnosis for Cryptosporidium oocyst. This modification has been used for the first time for better diagnosis of cryptosporidium oocysts.Key word: Cryptosporidiosis, patients with malignant disease, Mosul city.