Publications by authors named "Asok Kumar Mariappan"

8 Publications

  • Page 1 of 1

Molecular characterization of porcine circovirus 2 circulating in Assam and Arunachal Pradesh of India.

Anim Biotechnol 2021 Aug 10:1-5. Epub 2021 Aug 10.

Recombinant DNA Laboratory, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Bareilly, India.

PCV2 is the primary etiological agent of porcine circovirus-associated diseases (PCVADs) which affect pigs worldwide. Currently, there is a worldwide genotype prevalence switch from PCV2b to PCV2d, which has led to increased virulence of the circulating virus strains leading to vaccine failures and selection pressure. In the present study, the PCV2 genotypes circulating in north eastern region (NER) of India particularly the states of Assam and Arunachal Pradesh was characterized by isolation, sequencing and phylogenetic analysis of gene. The phylogenetic analysis revealed that the PCV2 isolates circulating in pigs of Assam and Arunachal Pradesh were mostly of PCV2d genotype. Hence, it can be concluded that PCV2d genotype is the most dominating genotype in NER and priority should be given to this genotype for development of future vaccine candidate against PCV2 in India.
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http://dx.doi.org/10.1080/10495398.2021.1955700DOI Listing
August 2021

Evaluation of the oncolytic property of recombinant Newcastle disease virus strain R2B in 4T1 and B16-F10 cells in-vitro.

Res Vet Sci 2021 Oct 25;139:159-165. Epub 2021 Jul 25.

Recombinant DNA Lab, Division of Veterinary Biotechnology, Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, India. Electronic address:

Recombinant Newcastle disease virus vectors have gained a lot of interest for its oncolytic virus therapy and cancer immune therapeutic properties due to its selective replication to high titers in cancer cells. The aim of this study was to find out the oncolytic effects of mesogenic recombinant NDV strain R2B-GFP on murine mammary tumor cell line 4T1 and murine melanoma cell line B16-F10. The anti-tumor effects of R2B-GFP virus were studied via expression of virus transgene GFP in cancer cells, evaluating its cytotoxicity and cell migration efficacies by MTT and wound healing assays respectively. In addition, the underlying apoptotic mechanism of R2B-GFP virus was estimated by TUNEL assay, colorimetric estimation of Caspase-3, 8 and 9 and the estimation of Bax to Bcl-2 ratio. The results showed a significant decrease in viability of both 4T1 and B16-F10 cells infected with R2B-GFP virus at 0.1 and 1 MOI. R2B-GFP virus could significantly induce apoptosis in the 4T1 and B16-F10 cells as compared to the uninfected control. Further, a flow cytometry analysis on apoptotic cells percentage and mitochondria membrane permeability test was also studied in R2B-GFP virus treated 4T1 and B16-F10 cell lines. The R2B-GFP virus caused an increase in loss of mitochondrial membrane permeability in both 4T1 and B16-F10 cells indicating the involvement of mitochondrial regulated cell death. Thus, the recombinant virus R2B-GFP virus proved to be a valid candidate for oncolytic viral therapy in 4T1 and B16-F10 cells.
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http://dx.doi.org/10.1016/j.rvsc.2021.07.028DOI Listing
October 2021

First description of natural concomitant infection of avian nephritis virus and infectious bronchitis virus reveals exacerbated inflammatory response and renal damage in broiler chicks.

Microb Pathog 2021 May 7;154:104830. Epub 2021 Mar 7.

Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, U.P, 243122, India.

We describe the first report on spontaneous Avian Nephritis Virus (ANV) and Infectious Bronchitis Virus (IBV) concurrent infection in broiler chicks. On necropsy, the kidneys were found swollen with its parenchyma and ureters stuffed with urate flakes. Histopathologically, the renal tubular damage and inflammatory response were severe in concurrently infected birds compared to the cases infected only with ANV, which had direct correlation with significantly (p < 0.001) increased expression of IL-1 β, IL-4, IL-12, IL-13, iNOS and IFN-γ transcripts in the kidneys of concurrently infected birds. Relative decrease in IFN-β transcript levels in the concurrently infected birds indicates suppression of antiviral response; the iNOS level was manifold increased which can be attributed to the enhanced macrophage response. Nucleotide sequencing of S1-spike glycoprotein gene of IBV and RNA dependent RNA polymerase gene of ANV confirmed etiologies as Igacovirus of Gammacoronavirus and ANV-2 of Avastrovirus 2, respectively. Both ANV and IBV virus affect kidneys. Our findings suggested that concurrent infections of these two viruses might have enhanced the transcripts of Th1, Th2 and proinflammatory cytokines with reduced IFN-β transcripts resulting in decreased host innate antiviral mechanisms leading to exacerbated renal lesions. Future experimental co-infection studies could throw more lights on pathology and pathogenesis during concurrent infections of ANV and IBV in poultry.
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http://dx.doi.org/10.1016/j.micpath.2021.104830DOI Listing
May 2021

Etiology, epidemiology, pathology, and advances in diagnosis, vaccine development, and treatment of infection in poultry: a review.

Vet Q 2020 Dec;40(1):16-34

Division of Pathology, ICAR - Indian Veterinary Research Institute, Bareilly, India.

is a Gram-negative bacterium of the family that resides normally in the respiratory and reproductive tracts in poultry. It is a major cause of oophoritis, salpingitis, and peritonitis, decreases egg production and mortality in hens thereby severely affecting animal welfare and overall productivity by poultry industries across Europe, Asia, America, and Africa. In addition, it has the ability to infect wider host range including domesticated and free-ranging avian hosts as well as mammalian hosts such as cattle, pigs and human. Evaluating the common virulence factors including outer membrane vesicles, fimbriae, capsule, metalloproteases, biofilm formation, hemagglutinin, and determining novel factors such as the RTX-like toxin GtxA, elongation factor-Tu, and clustered regularly interspaced short palindromic repeats (CRISPR) has pathobiological, diagnostic, prophylactic, and therapeutic significance. Treating this bacterial pathogen with traditional antimicrobial drugs is discouraged owing to the emergence of widespread multidrug resistance, whereas the efficacy of preventing this disease by classical vaccines is limited due to its antigenic diversity. It will be necessary to acquire in-depth knowledge on important virulence factors, pathogenesis and, concerns of rising antibiotic resistance, improvised treatment regimes, and novel vaccine candidates to effectively tackle this pathogen. This review substantially describes the etio-epidemiological aspects of infection in poultry, and updates the recent development in understanding the pathogenesis, organism evolution and therapeutic and prophylactic approaches to counter infection for safeguarding the welfare and health of poultry.
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http://dx.doi.org/10.1080/01652176.2020.1712495DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7006735PMC
December 2020

Immunomodulatory Potential of and CpG ODN (TLR21 Agonist) against the Very Virulent, Infectious Bursal Disease Virus in SPF Chicks.

Vaccines (Basel) 2019 Sep 4;7(3). Epub 2019 Sep 4.

ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, Uttar Pradesh, India.

Infectious bursal disease (IBD), caused by infectious bursal disease virus (IBDV), is characterized by severe immunosuppression in young chicks of 3 to 6 week age group. Although vaccines are available to prevent IBD, outbreaks of disease are still noticed in the field among vaccinated flocks. Further, the birds surviving IBD become susceptible to secondary infections caused by various viral and bacterial agents. This study assessed the immunoprophylactic potential of Cytosine-guanosinedeoxynucleotide (CpG) oligodeoxynucleotides (ODN) and stem aqueous extract in the specific pathogen free (SPF) chicks, experimentally infected with very virulent IBDV (vvIBDV). Both of these agents (CpG ODN and herbal extract) showed significant increase in the IFN-γ, IL-2, IL-4, and IL-1 levels in the peripheral blood mononuclear cells (PBMCs) ( < 0.05) of chickens in the treatment groups following IBD infection.Further we found significant reduction in mortality rate in vvIBDV infected chicks treated with either, or in combination, compared with the birds of control group. Additionally, the adjuvant or immune enhancing potential of these two immunomodulatory agents with the commercially available IBDV vaccine was determined in chicks. The augmentation of vaccine response in terms of an enhanced antibody titer after vaccination, along with either or a combination of the two agents was noticed. The findings provide a way forward to counter the menace of IBDV in the poultry sector through use of these herbal or synthetic immunomodulatory supplements.
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http://dx.doi.org/10.3390/vaccines7030106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6789546PMC
September 2019

Combination of TLR2 and TLR3 agonists derepress infectious bursal disease virus vaccine-induced immunosuppression in the chicken.

Sci Rep 2019 06 3;9(1):8197. Epub 2019 Jun 3.

Immunology Section, ICAR - Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, (243 122), India.

Live intermediate plus infectious bursal disease virus (IBDV) vaccines (hot vaccines) are used for protection against the virulent IBDV strains in young chickens. We evaluated the potential of Toll-like receptor (TLR) agonists to alleviate hot vaccine-induced immunosuppression. The combination of Pam3CSK4 and poly I:C synergistically upregulated IFN-β, IFN-γ, IL-12, IL-4, and IL-13 transcripts and cross-inhibited IL-1β, IL-10, and iNOS transcripts in the chicken peripheral blood mononuclear cells (PBMCs) as analyzed by quantitative real-time PCR. Further, four-week old specific pathogen free White Leghorn chickens (n = 60) were randomly divided into six groups and either immunized with hot IBDV vaccine with or without Pam3CSK4 and/or poly I:C or not vaccinated to serve as controls. The results indicated that poly I:C alone and in combination with Pam3CSK4 alleviated vaccine-induced immunosuppression, as evidenced by greater weight gain, increased overall antibody responses to both sheep erythrocytes and live infectious bronchitis virus vaccine, upregulated IFN-γ transcripts and nitric oxide production by PBMCs (P < 0.05), and lower bursal lesion score in the experimental birds. In conclusion, poly I:C alone and its combination with Pam3CSK4 reduced the destruction of B cells as well as bursal damage with restoration of function of T cells and macrophages when used with a hot IBDV vaccine.
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http://dx.doi.org/10.1038/s41598-019-44578-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6547722PMC
June 2019

Pathological and molecular investigation of velogenic viscerotropic Newcastle disease outbreak in a vaccinated chicken flocks.

Virusdisease 2018 Jun 3;29(2):180-191. Epub 2018 Apr 3.

1Avian Diseases Section, Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243 122 India.

Newcastle disease virus (NDV) belongs to genus and family Paramyxoviridae. There are thirteen serotypes named APMV-I (Avian Paramyxovirus-I) to APMV-13 of which NDV has been designated as APMV-1. The disease has been reported worldwide affecting both domestic and wild avian species. Morbidity and mortality rates up to 100% have been reported in cases of unvaccinated flocks. Stringent vaccination schedule is practiced in endemic/disease prone areas in order to prevent the disease. Despite this, NDV outbreaks have been reported even in cases of vaccinated populations. In this study we describe detailed pathological and molecular investigation that were undertaken in an organized poultry farm from Bareilly region, Uttar Pradesh, India, involving layer flocks which succumbed to ND outbreak in spite of following strict vaccination protocol. The mortality rate ranged from 76.80 to 84.41% in different flocks with an average mortality of 79.50%. Necropsied birds had gross lesions suggestive of viscerotropic ND including petechial hemorrhages on the proventricular tips, intestinal lumen with necrotic areas covered with hemorrhages, hemorrhagic cecal tonsils, para-tracheal edema and mottling of spleen. The characteristic histopathological lesions were mainly seen in the blood vessels and lymphoid tissues. Vascular changes characterized by congestion, edema, and hemorrhage were found in majority of the organs. Lymphocytolysis in spleen and cecal tonsils was evident. Immunohistochemical studies revealed positive signals mostly in macrophage and lymphocytes. PCR assay was done to confirm the NDV genome, which revealed an amplicon size of 356 bp. The phylogenetic analysis revealed the resemblance of the present isolate (ADS01) with class II genotype NDV XIIIA. The isolate belonged to velogenic NDV as the Minimum Lethal Dose (MLD) and Mean Death Time (MDT) for the present isolate were 10 and 41 h, respectively. Thus this study clearly demonstrates that in spite of strict vaccination regime and biosecurity procedures, ND continues to be rampant. Hence it is important to effectively administer the present vaccine in addition to strains matching to the field isolates to provide longer and optimal protection against spreading of virus by means of reducing the extent of viral shedding.
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http://dx.doi.org/10.1007/s13337-018-0445-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6003064PMC
June 2018

Hepato nephropathology associated with inclusion body hepatitis complicated with citrinin mycotoxicosis in a broiler farm.

Vet World 2018 Feb 4;11(2):112-117. Epub 2018 Feb 4.

Avian Diseases Section, Division of Pathology, ICAR - Indian Veterinary Research Institute, Izatnagar, Bareilly - 243 122, Uttar Pradesh, India.

Aim: Mortality in a broiler chicken farm was investigated for identifying the cause of mortality.

Materials And Methods: A broiler farm with a population of 16000 succumbed to a disease outbreak. Clinical signs, vaccination history and mortality, were recorded. Necropsy examination and microscopic examination were carried out along with toxicological and molecular studies.

Results: The clinical signs in the affected broiler birds were of non-specific nature with a total mortality of 26.39%. Postmortem examination and microscopical findings revealed hepatitis with basophilic intranuclear inclusion, splenitis, myocarditis, and nephritis. Glomerulonephritis was the prominent renal pathology recorded in this study. Polymerase chain reaction test confirmed the presence of fowl adenovirus (FAdV) genome in the target organs, and toxicological examination by thin-layer chromatography revealed the presence of a toxic level of citrinin in the feed samples.

Conclusion: Based on various diagnostic investigations, the mortality in the flock was attributed to inclusion body hepatitis (IBH) complicated with citrinin mycotoxicosis. Thus, apart from liver pathology which occurs in a classical IBH cases, glomerulonephritis too occurs which are also a prominent finding which pathologists often miss. Thus, kidneys should also be examined histologically to assess the microscopic tissue alterations in poultry suspected for IBH along with a mycotoxicological analysis of feed. This will definitely throw light on the synergistic pathology elicited and exhibited by FAdV and mycotoxins in the poultry.
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http://dx.doi.org/10.14202/vetworld.2018.112-117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5891860PMC
February 2018
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