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
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Creator |
Balasubramaniam, A.
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Contributor |
Dorairajan, N.
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Subject |
Infectious bronchitis virus
Nephropathogenicity Sequencing Pathotyping Protectotyping Maternal antibody |
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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. |
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Date |
2016-07-26T14:10:23Z
2016-07-26T14:10:23Z 2010 |
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Type |
Thesis
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Identifier |
http://krishikosh.egranth.ac.in/handle/1/69932
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Language |
en
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Format |
application/pdf
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Publisher |
Tamil Nadu Veterinary and Animal Sciences University
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