author(s)
Zaid Haddam Taha, Aida Bara Allawe, Mayada Jawad Kadhum and Amer Abdulameer Abbas

abstract
This study concerned with isolation and diagnosis of avian infectious laryngotracheitis (ILT) virus in Iraq by different diagnostic methods. Fifty laryngeal and tracheal samples were collected from Al-Taji, Diala, Al-Sowara, Al-Mahmodia, Al-Kut-Azizah, Al-Diwania, Holy-Karbala, Al-Hilla, and Al-Najaf from January-August/2016 for isolation of ILT virus. Infectious laryngotracheitis (ILT) virus was isolated from three samples out of fifty samples. The positive samples were collected from Al-kut, Diala and Diwania. Chicken embryo fibroblast (CEF) cell culture was used for isolation of ILT virus. Cytopathic effects of isolated virus on CEF were rounded of cells with foci of degenerated cells and formation of giant cells. The titer of isolated virus was 10^3.16 TCID 50/50ml on third passage, the titer of virus was increased on fourth passage to 10^4.7TCID 50/50ml. Pock lesions were detected on Chorio-allantoic membrane of chicken embryos after five days post inoculation with isolated virus at 12 days. Sequence analysis of one wild isolate revealed that 99% nucleic acid identity over 266 bp of glycoprotein H gene (265/266bp) to different data bases entries. Based on sequenced region identical relation to field strains GHV1 strain 81658 as well as to vaccine strains GHV-1 vaccine laryngeo Vac has been identified.