Infectious Laryngo Tracheitis Virus in Chicken

A study was undertaken to isolate, identify and characterize the causative agent of Infectious laryngotracheitis (ILT) in layers from field outbreaks in Namakkal area.The maximum prevalence was noticed in the age group of 10 to 20 weeks (40.47 %) followed by 20 to 30 weeks (26.19 %). The field isolates were confirmed by Agar Gel Precipitation Test and histopathology.Molecular characterization of the field ILTV isolates were carried out by amplification of ICP4 gene and Tk gene by polymerase chain reaction and produced amplicons size of 635 bp and 649 bp respectively.Restriction endonuclease analysis of ILTV field isolates were carried out for the Tk gene amplicons size of 649 bp with endonuclease enzymes viz. HaeIII, Sau 96I and NciI and two for Hae III ,Three for Sau 96I and no cleavage for NciI were observed.The sequence analysis showed that the homology of nucleotide sequences between field isolates was 99.2 100 per cent for ICP4 gene and 96.5 -100 per cent for the Tk gene. The protein profile of field ILTV isolates and vaccine strain were studied by SDS PAGE which yielded 60, 85,160 and 205 kDa. A dot-ELISA technique was developed for detection of ILTV from field samples.