ABSTRACT
AIDS is acquired by infection with HIV [human immuno-deficiency virus]. It leaves the host susceptible to malignant and unusual infections especially opportunistic ones. Most of AIDS patients infected with opportunistic parasitic infections die because of chronic diarrhea and deaths due to Cryptosporidium diarrhea in AIDS patients are considerable in the recent two decades. The aim of this study is to find Cryptosporidium parasite in AIDS patients referring to the center of Diseases consultation in Kermanshah province and to determine the frequency of infection in those patients. In this study stool and blood samples were collected from 75 AIDS patients referring regularly to the Center of Diseases Consultation in Kermanshah and the gathered information were filled in the questionnaires together with their personal information regarding their names, sex and etc. Stool samples were tested using direct and formalin ether methods and then the smears that were dyed using modified acid fast staining were examined. Peripheral blood samples were used to determine the CD4 counts. The results showed that the frequency of infection with Cryptosporidium in AIDS patients was 26.7% [20 cases]. According to the study, as the number of CD4 decreased in the patients, the probability of infection with opportunistic parasites increased and increase in the number CD4 that is normally accompanied with strengthening the body immune system resulted in the decrease in the frequency of infection with Cryptosporidium