Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 10 1 2015 03 15 69 77 EN Hossein Hamidinejat Dept. of Pathobiology, Veterinary Faculty, Shahid Chamran University of Ahvaz, Ahvaz, Iran. Massoud Reza Seifi Abad Shapouri Dept. of Pathobiology, Veterinary Faculty, Shahid Chamran University of Ahvaz, Ahvaz, Iran. Mohammad Mehdi Namavari Razi Vaccine and Serum Research Institute, Shiraz Branch, Shiraz, Iran. Parviz Shayan Dept. of Parasitology, Veterinary Faculty, University of Tehran, Tehran, Iran. Marzieh Kefayat Dept. of Parasitology, Shahid Chamran University of Ahvaz, Ahvaz, Iran. 2015 10 14   Background: Dense granules are immunodominant proteins for the standardi-zation of immunodiagnostic procedures to detect neosporosis. In the presented study different fragment of a dense-granule protein was evaluated for serodiagno-sis of Neospora caninum in cattle and water buffalo. Methods:NcGRA7, from N. caninum tachyzoites was amplified. PCR product and pMAL-c2X plasmid were digested with EcoR1 restriction enzyme and ex-pressed in Escherichia coli to evaluate its competence for detection of anti- N. cani-num antibodies with ELISA in comparison with commercial IDEXX ELISA. Fur-thermore, 230 sera of presumably healthy cattle and water buffaloes (108 cattle and 122 water buffaloes) were analyzed by both tests to determine the agreement of these two procedures. Results:Sensitivities and specificities of NcGRA7-based ELISA were 94.64% and 90.38% respectively using sera of cattle, but were 98.57% and 86.54% in the case of buffaloes respectively. A good correlation between the results of IDEXX ELISA and ELISA based on recombinant NcGRA7 for detecting N. caninum an-tibodies was appeared. Analyzing by Mc Nemar´s showed that NcGRA7-based ELISA has acceptable capability to differentiate the positive results in comparison with IDEXX ELISA. Conclusion:NcGRA7-based ELISA considering utilized new fragment of ge-nomic DNA is a good tool for serodiagnosis of anti- N. caninum antibodies for screening and epidemiological purposes on cattle herd and water buffaloes as well. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/350 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/350/425