Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 9 4 2014 12 15 482 490 EN Elahe Ebrahimzade Department of Parasitology, Iranian Center for Ticks and Tick-borne Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Parviz Shayan Department of Parasitology, Iranian Center for Ticks and Tick-borne Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Zeinab Asghari Department of Parasitology, Iranian Center for Ticks and Tick-borne Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Sedighe Jafari Department of Parasitology, Iranian Center for Ticks and Tick-borne Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. Zahra Omidian Department of Parasitology, Iranian Center for Ticks and Tick-borne Diseases, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. 2015 10 14 Background: Cryptosporidium parvum causes severe gastroenteritis in immunocompromised human and new borne animals. The organism can be transmitted through water. Since small number of C. parvum is infectious, the aim of the present study was to develop a chromatography method for the isolation of C. parvum oocyst in samples with limited number of oocysts. Methods: Antibody was prepared against whole antigen from C. parvum oocysts, the achieved Ab bound to the sepharose 4B and used for the isolation of oocysts. Antibody against P23 bound to the sepharose 4B, used also for the isolation of C. parvum oocyst. In comparison to these both methods, 2 traditional methods (Salt floatation and 55% sucrose floatation) were also performed. Results: Both chromatography methods could bind oocysts with capacity depends on the column size. The isolated oocysts were free of bacteria. Our results showed that the traditional methods are useful for the isolation of oocysts from feces, in its smear stained with ziehl-nelsen, at least 3 oocyts are detectable in each microscopic field under 1000 X magnification. In contrast to the chromatography methods, the bacterial contamination was always observed in oocysts isolated with traditional methods. Conclusion: Immunochromatography could be used for the successful isolation of C. parvum oocysts from the samples containing limited number of oocysts. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/374 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/374/370