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Study on Viruses Associated with Nephropathy in Poultry with Special Reference to Infectious Bronchitis Virus

KrishiKosh

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Title Study on Viruses Associated with Nephropathy in Poultry with Special Reference to Infectious Bronchitis Virus
 
Creator Balasubramaniam, A.
 
Contributor Dorairajan, N.
 
Subject Infectious bronchitis virus
Nephropathogenicity
Sequencing
Pathotyping
Protectotyping
Maternal antibody
 
Description A study was undertaken to identify and characterize the viruses causing nephritis
in poultry with special reference to IBV in Tamil Nadu and Karnataka. Out of 14 broiler
chicken kidney samples and 8 layer chicken kidney samples yielding a titre of 1:16 and
above in IBV-specific HA test, 11 samples (79.0 per cent) in broiler chicken and two
samples (25.0 per cent) in layer chicken were positive for IBV isolation in ECE of SPF
origin. IBV-specific HA test can be a viable screening method for nephropathogenic IBV
in broiler type of chickens.
Reverse Tranciptase Polymerase Chain Reaction for partial M and N genes was
carried out to amplify1020 bp and RT-PCR for entire S1 gene to amplify 1700 bp. Direct
sequencing of partial M and N genes of the isolates Ind/KA/07/1 and Ind/TN/07/2 was
carried out. Multiple sequence alignment for membrane glycoprotein and 5b protein of N
gene with reference strain M41 revealed many point mutations, short deletions and
insertions. Phylogenetic analysis of the amplified part of the isolates indicated that these
were Mass variants. The isolate Ind/KA/07/1 showed more variation in these alignments
and restriction site mapping than isolate Ind/TN/07/2. The isolates might have probably
emerged under selective pressure due to vaccination.
RFLP of S1 gene using restriction endonucleases viz. AluI, EcoRI, HaeIII and
SalI revealed that AluI was able to discriminate the isolates as it grouped the isolates
Ind/TN/07/1, Ind/TN/07/2, Ind/KA/07/1, Ind/KA/07/2 and Ind/KA/07/4 into one along with
vaccine strain H120 and the isolates Ind/KA/07/6 and Ind/KA/07/8 differently.
Seven IBV field isolates were subjected for the pathotyping trial in broiler
chickens. All the samples obtained from dead chicks and those sacrificed on 7 and 14
dpi were positive in producing embryo lesions characteristic of IBV after three passages
in ECE. All the chicks died showed pale, enlarged kidneys and urate deposit in ureters.
Microscopically, kidney showed severe vascular congestion and intertubular
haemorrhage. Most severe lesions such as single cell necrosis, necrosis of tubular
epithelial cells and interstitial infiltration of lymphocytes and plasma cells were observed
during 14 and 21 dpi.
Nephropathogenicity of the IBV field isolates was determined by giving score
based on microscopic renal lesions induced in chicks died due to nephritis. The isolates
Ind/KA/07/1 and Ind/TN/07/2 had the highest score of 1.33 whereas the isolate
Ind/KA/07/6 scored an index of 1.17. All other isolates scored mean index score of 1.0
and below.
The isolate Ind/KA/07/1 took 28 passages to get attenuated while Ind/TN/07/2
took 25 passages to get attenuated. Both live attenuated isolates elicited protective
response by second week after vaccination during protectotyping trial. Inactivated
vaccine was prepared using isolate Ind/KA/07/6. Egg yolk prepared on 28 dpv from hens
vaccinated with inactivated Ind/KA/07/6 isolate showed a titre of 415.9 and 15188±768 in
HI test and ELISA respectively. The HI test and ELISA indicated that level of maternal
antibody (MAb) in the vaccine group was significantly (P< 0.01) higher on seven days of
age. However, it decreased to below the protection level in vaccine group in two weeks
of age. In nephropathogenic IB, partial protection against homologous and poor crossprotection
against heterologous challenge was evident in pathotyping and transfer of
MAb trials.
 
Date 2016-07-26T14:10:23Z
2016-07-26T14:10:23Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/69932
 
Language en
 
Format application/pdf
 
Publisher Tamil Nadu Veterinary and Animal Sciences University