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

Tht: clinical signs and postmortem lindings including rt:spiratory system distress and Icsions in upper respiratory tract wert: observed in 17 commercial layer flocks l'rom differcnt parts of Iran. Laryngotracheal tissues l'rom the alTeetcd birds with suspectcd inlectious laryngotrachitis (lLT) wcrc examined l'or deteetion of the causative agt:nt using virus isolation (VI), agar gd imlllunodilTusion (AGIO), histopathology (HP), and polylllcrase chain reaction (peR). 12 (70.5%) of the salllples were formed typical poeks on chrioallantoic membrane of embryonated specilic pathogen free eggs in VI method. By AGIO test Il (64.7%) of the samples \Vere detectcd as II.T virus (1I.Tv) that gave c1ear lines \Vith hyperimmune IL T serum. Of the samples 7 (41.1 %) were illustrated lesions chara\.:teristics of ILT including inliltration of inllammatory œlls and syncytia formation. In 14 (82.3%) or the salllples ILTv was dcteetcd h) l'CR. The high positive perccntages of the l'CR indieate that the technique is applicable in rapid diagnosis of ILT for its accurucy, sensitivity and specilieity.