The Morphological investigations of experimental avian encephalomyelitis in turkey embryo

29 7. SUMMARY jn this study, pathological changes induced by Avian Encephalomyelitis virus (AE) in Turkey embryos were analysed microscopically and macroscopically. For this purpose, 0.1 ml AE virus (Van Roekel Strain AEV-VR) at Embryo Infective Dose 50 of 10~5 diluted in sterile saline at 1/10 ratio was given to 7 day embryonated turkey eggs via yolk sac. Starting on day 11, until the chicks hatched, every day 4 embryos were taken out of the incubator and examined for pathological changes. Control embryos were not injected with virus solution two control embryos were examined daily. The rump lengths and widths and weights of embriyos were measured. After the necropsy, tissue samples from brain, cerebellum, spinal cord (cervical, thoracal and lumbosacral regions) muscular stomach, the pancreas, the lungs, the liver, heart muscle, skeletal muscle, the eyes, and chorioallantoic membranes were collected. After hemotexylen eosin staining, (in same cases Woelcke staining) the tissue samples were examined under the microscope. Gross macroscopic examination, revealed that in infected embryos, loss of movement, retardation in growth, cerebral edema, torticollis, cataract and deformities in the legs and feet were present. The differences between the test and control embriyos in the rump width, rump length, and in total weight started to be noticed on 15th and 16th days of incubations. For the first time, on 17th and 18th days cerebral edema, on 19th and 20th days torticollosis, on 213t and 22Rd days cataract were noticed.SO Microscopically, vascular proliferation, edema, gliosis and neuronal necrosis and degeneration in the brain, gliosis, neuronal necrosis, and degeneration in the medulla spinalis, cataract in the eyes, hyalin degeneration, necrosis and dystrophy in the skeletal muscles were observed. Compored to macroscopic lesions, microscopic findings started earlier (11th and 12th days of incubation). As the embryos aged, the severity of microscopic lesions increased.