MOLECULAR DETECTION AND HISTOPATHOLOGICAL STUDIES OF COMMON VIRAL RESPIRATORY INFECTIONS IN CHICKEN
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Date
2018
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES, POOKODE WAYANAD
Abstract
An assembly of viruses can cause diseases in chicken and cause many economically
important diseases in them. The common viruses affecting respiratory system of chicken
include Infectious Bronchitis virus (IBV), Newcastle Disease virus (NDV), Fowl Pox virus
(FPV), Infectious Laryngotracheitis (ILTV) and Avian Metapneumovirus (aMPV). A
comprehensive study was done to detect the presence of IBV, NDV, FPV, ILTV and
aMPV in chickens in Wayanad district of Kerala. The tissue samples collected from 50
dead birds and nasal swabs and serum samples from few live birds of different regions of
the district were utilized for the study. The tissue samples were examined for gross lesions
as well as histopathological lesions after formalin fixation and further tissue processing.
Most of the clinical signs like unthriftiness, respiratory distress, gasping, sneezing and
nasal discharge and lesions like pulmonary congestion, haemorrhage, thrombus, oedema
and bronchial epithelial damage observed were in comparison with the lesions usually
noticed in respiratory viral infections. Molecular detection was also carried out after RNA/
DNA extraction. For IBV detection, nested reverse transcription polymerase chain
reaction (RT-PCR) targeting N gene region was carried out and eight samples were
detected as positive giving a percentage positivity of 16 per cent. By sequencing and
BLAST analysis, it was found that IBV isolate has similarity with Chinese isolates. For
NDV detection, RT-PCR targeting M and F gene region were done and one sample was
detected as positive (two per cent). On BLAST analysis, it was found that NDV isolates
had much similarity to other Indian isolates. For FPV detection, PCR targeting 4b gene
was carried out and only one sample was detected as positive. On BLAST analysis, it
showed much similarity to Hungarian and Mozambique isolates. For ILTV detection, PCR
targeting gB gene and for aMPV detection, RT-PCR targeting M gene was carried out and
none of the samples were detected as positive. The study could successfully detect the
presence of Infectious Bronchitis, Newcastle Disease and Fowl Pox in the poultry
population in Wayanad district of Kerala.
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