Isolation and Identification of Infectious Laryngotrachitis Virus from Commercial Flocks of Iran Using Various Techniques

Abstract

Summary The clinical signs and postmortem findings including respiratory system distress and lesions in upper respiratory tract were observed in 17 commercial layer flocks from different parts of Iran. Laryngotracheal tissues from the affected birds with suspected infectious laryngotrachitis (ILT) were examined for detection of the causative agent using virus isolation (VI), agar gel immunodiffusion (AGID), histopathology (HP), and polymerase chain reaction (PCR). 12 (70.5%) of the samples were formed typical pocks on chrioallantoic membrane of embryonated specific pathogen free eggs in VI method. By AGID test 11 (64.7%) of the samples were detected as ILT virus (ILTV) that gave clear lines with hyperimmune ILT serum. Of the samples 7 (41.1%) were illustrated lesions characteristics of ILT including infiltration of inflammatory cells and syncytia formation. In 14 (82.3%) of the samples ILTV was detected by PCR. The high positive percentages of the PCR indicate that the technique is applicable in rapid diagnosis of ILT for its accuracy, sensitivity and specificity.