ABSTRACT
Leucocytozoonosis is a disease of birds caused by obligate intracellular protozoa of the genus Leucoytozoon. We determined the prevalence of Leucocytozoon spp. using light and transmission electron microscopy in domestic birds in southwest of Iran. 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. 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. Leucocytozoonosis are distributed in the Lorestan province bird population and electron microscopy can resolve the problem to distinguish between similar species of Leucocytozoon