Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 8 1 2013 03 15 171 176 EN O Dezfoulian Department of Pathobiology, Faculty of Veterinary Medicine, Lorestan University, Khorram Abad, Iran. M Zibaei Department of Parasitology and Mycology, School of Medicine, Lorestan University of Medical Sciences, Khorram Abad, Iran. H Nayebzadeh Department of Pathobiology, Faculty of Veterinary Medicine, Lorestan University, Khorram Abad, Iran. M Haghgoo Office of Agriculture Insurance Found, Lorestan Province, Khorram Abad, Iran. An Emami-Razavi Department of Pathology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. K Kiani Department of Pharmacology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. 2015 10 14  Background: Leucocytozoonosis is a disease of birds caused by obligate intracellular protozoa of the genus Leucocytozoon. We determined the prevalence of Leucocytozoon spp. using light and transmis-sion electron microscopy in domestic birds in southwest of Iran. Methods: A total of 825 blood smears from 275 birds were examined for presence of infection. The structure morphology of Leucocytozoon spp. was studied using light and electron microscopy. Results: Forty-four (16.0%) of the birds were positives for Leucocytozoon. The detected parasite were found in 14 chickens (5.1%), 12 geese (4.3 %), 10 ducks (3.6%), and 8 turkeys (2.9%). The majority of the records were from the northeastern regions. Conclusion: Leucocytozoonosis are distributed in the Lorestan province bird population and elec-tron microscopy can resolve the problem to distinguish between similar species of Leucocytozoon. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/510 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/510/414