RESUMEN
Biliary and duodenal aspirates were collected from 60 patients to detect Cryptosporidium parvum [C. parvum] and microsporidial species in obstructive biliary diseases. Patients were classified into three groups: Group I, benign obstructive biliary diseases [30 cases]; Group II, malignant obstructive biliary diseases [30 cases] and Group III, ten normal persons served as controls. C. parvum oocysts were detected in higher percentage in malignant obstructive biliary diseases than benign obstructive biliary diseases, but no oocysts were detected in stool samples. Microspora was also detected in higher percentage in group II than group I. Concerning types of obstructive biliary diseases in benign type, C. parvum and microspora were detected with a higher percentage in calcular type than stricture or dyskinesia. In malignant obstructive group, a higher percentage of C. parvum oocysts was detected in carcinoma of biliary tree