Isolation and Molecular Characterization of Infectious Laryngotracheitis Virus from Naturally Infected Layer Chicken Flocks in Egypt

摘要

Infectious Laryngotracheitis (ILT) is an acute viral disease affecting the respiratory tract of chickens.The present study was conducted for the isolation and molecular characterization of ILT viruses in layerchickens from commercial farms located in four provinces in the Egyptian Nile Delta. In the embryonatedchicken eggs (ECE), virus produced white pock lesions on the chorioallantoic membrane (CAM) after the thirdegg passage. Histopathological examination of ILTV infected CAM revealed the presence of intranuclearinclusion bodies in the infected cells. The identity of the ILT viruses was confirmed by polymerase chainreaction assay (PCR) amplification of a 647bp fragment of thymidine kinase TK gene with subsequentsequencing and phylogenetic analysis. Sequence analysis of the TK gene of the isolates revealed genetic (99-100%) homology to most of the previously published strains.