Displaying publications 1 - 20 of 80 in total

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  1. Ugwu CC, Hair-Bejo M, Nurulfiza MI, Omar AR, Aini I
    Open Vet J, 2023 Feb;13(2):171-178.
    PMID: 37073244 DOI: 10.5455/OVJ.2023.v13.i2.4
    BACKGROUND: Fowl adenovirus (FAdV) 8b and other serotypes cause inclusion body hepatitis (IBH) in chickens. Specific detection of aetiologic serotype in mixed infection and vaccine failure could be difficult.

    AIM: The objective of this study was to develop a TaqMan probe-based qPCR method for the detection and quantification of the FAdV 8b challenge virus.

    METHODS: Forty-eight broiler chickens inoculated with live attenuated or inactivated FAdV 8b strains at day 1 of age either with or without booster at day 14 post-inoculation were used. The chickens were challenged with a pathogenic strain of FAdV 8b at day 28 of age. Liver and cloacal swabs were collected on days 7 and 14 post-challenge. Primers and probes were designed, specificity confirmed, and used to carry out qPCR amplification.

    RESULTS: The assay amplified the FAdV DNA challenge virus, but not that of the live attenuated virus. It could detect FAdV 8b DNA as low as 0.001 ng/µl in liver and cloacal swab samples. Copy numbers obtained indicate virus load and shedding.

    CONCLUSIONS: It shows that a selective detection of FAdV 8b within serotype is possible. It can be useful for rapid detection and diagnosis of the disease, virus quantification and differentiation within species, determination of vaccination failure, and efficacy especially the virus load in the target organ and shedding.

  2. Ugwu CC, Hair-Bejo M, Nurulfiza MI, Omar AR, Ideris A
    Vet World, 2022 Nov;15(11):2681-2692.
    PMID: 36590109 DOI: 10.14202/vetworld.2022.2681-2692
    BACKGROUND AND AIM: Fowl adenovirus (FAdV) 8b causes inclusion body hepatitis, resulting in major economic losses globally among chickens. The objectives were to inactivate FAdV 8b isolate propagated in chicken embryo liver (CEL) cells using a stirred tank bioreactor (UPM08136P5B1) and determine the humoral and cell-mediated immune response, efficacy, and virus shedding in broiler chickens.

    MATERIALS AND METHODS: The FAdV 8b isolate UPM08136P5B1 was inactivated using binary ethyleneimine, adjuvanted with Montanide 71VG, inoculated into day-old broiler chickens in a booster group (BG) and non-booster group (NBG), and challenged with a pathogenic FAdV 8b strain. Clinical signs, gross lesions, body weight (BW), liver: body weight ratio, FAdV antibody titer using enzyme-linked immunosorbent assay, and histopathological changes were recorded. The CD3+, CD4+, and CD8+ T-lymphocyte profiles of the liver, spleen, and thymus using flow cytometry, and viral load in liver and cloacal shedding using quantitative polymerase chain reaction were evaluated.

    RESULTS: Chickens in the challenged control group (CCG) exhibited mild clinical signs, gross lesions, and histopathological changes, which were absent in the inoculated groups, and had lower BW and higher liver BW ratio than chickens in the unchallenged control group (UCG); BG and NBG on 35- and 42-days post-inoculation (DPI). Chickens in NBG and BG had higher antibodies than UCG on 7, 21, 35, and 42 DPI. The challenged BG and NBG produced higher antibodies than the CCG on 35 DPI. T-lymphocytes were higher among the inoculated groups than UCG in the liver, spleen, and thymus. Inoculated challenged groups recorded higher CD3+, CD4+, and CD8+ T-lymphocytes on 35 and 42 DPI than CCG. The challenged control group had a significantly higher viral load in the liver than challenged that in BG on 35 DPI and BG and NBG on 42 DPI. The challenged control group had significantly higher challenge FAdV shedding than challenged inoculated groups on 35 and NBG on 42 DPI.

    CONCLUSION: UPM08136P5B1 was successfully inactivated and mixed with Montanide 71VG. The inactivated vaccine candidate that induced humoral and cellular immunity was effective, reduced FAdV load in the liver, and shedding in the cloaca, and could be useful against FAdV 8b infections in chickens.

  3. Hamisu TM, Aliyu HB, Tan SW, Hair-Bejo M, Omar AR, Ideris A
    Avian Dis, 2022 Sep 22.
    PMID: 36198006 DOI: 10.1637/aviandiseases-D-22-00029
    In spite of the available information on the role of natural killer (NK) cells in several viral infections, the interactions between chicken intraepithelial-NK (IEL-NK) cells and Newcastle disease virus (NDV) are poorly understood. In this study, we investigated these interactions following the inoculation of chickens with NDV vaccine strain LaSota and subsequent challenge with velogenic NDV (vNDV) genotype VII (GVII) and VIII (GVIII), through quantification of IEL-NK cell's apoptosis and expression profiling of its surface receptors. Specific-pathogen-free chickens were randomly divided into six groups, as follows: one group of an uninfected control, one group infected with NDV LaSota, two groups each infected with either GVII or GVIII, and two groups inoculated with NDV LaSota and challenged with either GVII (LaSota-genotype VII [LSGVII]) or GVIII (LaSota-genotype VIII [LSGVIII]). Avian intraepithelial lymphocytes (IEL) were isolated from the duodenal loops, and CD3- cells were characterized. Immunophenotyping and apoptosis analysis of CD3-/CD25+/CD45+IEL NK cells were conducted using a flow cytometer. In addition, a gene expression study was conducted using real-time quantitative PCR. Data were analyzed using two-way analysis of variance. The results showed that vNDV GVII or GVIII caused apoptosis of IEL-NK cells; however, following inoculation of LSGVII or LSGVIII, the effect of vNDV GVII and GVIII to cause a reduction in the population of viable IEL-NK cells was significantly reduced. Furthermore, the expression profiles of activating receptors CD69, NK-lysin, and IFN-γ, were generally upregulated in chickens inoculated with LSGVII or LSGVIII. In contrast, B-NK, an inhibitory receptor, was downregulated in these treatment groups. In NDV GVII- and GVIII-challenged groups, however, B-NK was upregulated, whereas the other receptors were generally downregulated. The findings of this study showed that NDV vaccine strain LaSota may prevent apoptosis and cause upregulation of activating receptors of chicken IEL-NK cells in velogenic virus-challenged settings.
  4. Aliyu HB, Hamisu TM, Hair Bejo M, Omar AR, Ideris A
    Avian Pathol, 2022 Feb;51(1):76-86.
    PMID: 34842475 DOI: 10.1080/03079457.2021.2006604
    Variant infectious bursal disease virus (vaIBDV) has been identified in various countries with significant economic losses. Recently, the first identification of a variant strain in Malaysia was reported. The pathogenicities of the Malaysian variant, UPM1432/2019, and very virulent infectious bursal disease virus (vvIBDV), UPM1056/2018 strains were comparatively evaluated in specific-pathogen-free (SPF) chickens based on gross and histopathological examinations and viral load. Four-week-old SPF chickens were randomly divided into three groups; group 1 served as the control, while groups 2 and 3 birds were challenged with the vaIBDV and vvIBDV, respectively. Three birds from each group were weighed, euthanized and necropsied at 2, 3, 4, 5, 7 and 21 days post-challenge (dpc). Unlike UPM1056/2018 group, birds from UPM1432/2019 group did not show clinical signs or death. UPM1056/2018 strain caused 11% mortality rate in the infected chickens. The bursal body index (BBIX) for UPM1432/2019- and UPM1056/2018-infected groups was <0.7 from 2 dpc and continued to decrease to 0.49 and 0.45, respectively, at 21 dpc. UPM1432/2019 strain was more persistent in the bursa than UPM1056/2018 strain. Both strains induced similar pathological lesions in SPF chicks. These results indicate that the Malaysian vaIBDV severely damaged the immune organs of chickens and was more persistent in bursal tissue than vvIBDV. The study provides insight into the pathogenicity of the variant strain as further study may be required to evaluate the efficacy of the currently available IBD vaccines in Malaysia against the strain. RESEARCH HIGHLIGHTSEmerging Malaysian variant IBDV caused severe bursal damage without mortality.Atypical vvIBDV induced bursal atrophy with inflammatory response and caused low mortality.Malaysian variant IBDV was more persistent in bursal tissue than vvIBDV.
  5. Ahmad S, Hair-Bejo M, Hussein EA, Awad EA, Saeed MI, Liew PS, et al.
    Open Vet J, 2022;12(6):839-850.
    PMID: 36650863 DOI: 10.5455/OVJ.2022.v12.i6.8
    BACKGROUND: The studies about Salmonella infection in newly hatched chicks were not extensive.

    AIM: The objective of this study was to determine the pathogenicity of Salmonella enterica subspecies enterica serovar Enteritidis (SE) phage type (PT) 1 in one-day-old specific pathogen-free (SPF) chicks.

    METHODS: Seventy, one-day-old SPF chicks, were divided into SE group (30 chicks), mortality group (10 chicks), both orally inoculated (1.0 ml) with SE PT1 (1 × 108 colony-forming unit per 1.0 ml), and one control group (30 chicks). The chicks were sacrificed at 6 and 12 hours, and days 1, 2, 3, 5, 7, 10, 14, and 21 post-inoculation (pi). Samples were collected for bacterial isolation, histological examination, and ultrastructural examination.

    RESULTS: Starting from day 2 pi, the body weight in the SE group significantly (p < 0.05) decreased. The SE isolation percentages from the liver, spleen, mid-intestinal content, cecal content, cecal tonsil, blood, and cloacal swab were 0.73, 0.77, 0.33, 0.33, 0.36, 0.40, and 0.30, respectively. The isolation percentage in the liver was significantly (p < 0.05) higher than the blood and cloacal swab. The villi heights and crypt depths in the SE group were significantly (p < 0.05) greater and smaller, respectively. Ultrastructurally, erosion and necrosis were observed in the microvilli of the cecal tonsil. The bacteria were engulfed by macrophages at the interepithelial clefts of the M-like M cells.

    CONCLUSION: It was concluded that the inoculation of SE PT 1 in one-day-old chicks caused a systemic infection with diarrhea, a decrease in the body weight and villi height in the duodenum, jejunum, and ileum, and high bacterial loading in the liver with mild gross and histological lesions of organs, erosion, and necrosis of microvilli and low mortality. The bacteria entered the body system from the intestinal tract through the interepithelial clefts of the M-like M cells of the cecal tonsil.

  6. Sohaimi NM, Hair-Bejo M
    Open Vet J, 2021 10 19;11(4):569-580.
    PMID: 35070851 DOI: 10.5455/OVJ.2021.v11.i4.6
    Fowl adenovirus (FAdV) is a double-stranded DNA virus with a non-enveloped structure comprising three major proteins known as hexon, penton, and fiber. Molecular analysis which emphasizes on hexon and fiber proteins is currently the major focus of curiosity for FAdV antigenicity and pathogenicity. Recently, disease outbreaks associated with FAdV infections such as inclusion body hepatitis, hepatitis hydropericardium syndrome, and gizzard erosion, were commonly reported and continue to increase worldwide. Studies on the virulence gene of the virus were intensively conducted to provide a better understanding on the role of these major capsid proteins in the development of a safe and effective vaccine against the disease in the poultry industry. This paper highlights the variations of the fiber and hexon genes, their importance in genotypes and serotypes differentiation, and infectivity between FAdV strains. It appears that the L1 loop of hexon and the knob of fiber genes are the infectivity markers for FAdV infection. The fiber-2 protein plays a major role in FAdV pathogenicity than the hexon protein, while the fiber-1 protein is important for viral replication and assembly, regardless of virulence capability instead of infectivity. The hexon protein plays a major role in virus infectivity and tissue tropism. These findings could further enhance the knowledge of FAdV strains' classification and evolution, diagnosis, and strategies to prevent and control FAdV infection and outbreaks in chicken farms.
  7. Azli B, Ravi S, Hair-Bejo M, Omar AR, Ideris A, Mat Isa N
    BMC Genomics, 2021 Jun 19;22(1):461.
    PMID: 34147086 DOI: 10.1186/s12864-021-07690-3
    BACKGROUND: Infectious bursal disease (IBD) is an economically very important issue to the poultry industry and it is one of the major threats to the nation's food security. The pathogen, a highly pathogenic strain of a very virulent IBD virus causes high mortality and immunosuppression in chickens. The importance of understanding the underlying genes that could combat this disease is now of global interest in order to control future outbreaks. We had looked at identified novel genes that could elucidate the pathogenicity of the virus following infection and at possible disease resistance genes present in chickens.

    RESULTS: A set of sequences retrieved from IBD virus-infected chickens that did not map to the chicken reference genome were de novo assembled, clustered and analysed. From six inbred chicken lines, we managed to assemble 10,828 uni-transcripts and screened 618 uni-transcripts which were the most significant sequences to known genes, as determined by BLASTX searches. Based on the differentially expressed genes (DEGs) analysis, 12 commonly upregulated and 18 downregulated uni-genes present in all six inbred lines were identified with false discovery rate of q-value

  8. Aliyu HB, Hair-Bejo M, Omar AR, Ideris A
    Front Vet Sci, 2021;8:643976.
    PMID: 33959650 DOI: 10.3389/fvets.2021.643976
    Vaccination is an essential component in controlling infectious bursal disease (IBD), however, there is a lack of information on the genetic characteristics of a recent infectious bursal disease virus (IBDV) that was isolated from IBD vaccinated commercial flocks in Malaysia. The present study investigated 11 IBDV isolates that were isolated from commercial poultry farms. The isolates were detected using reverse transcription-polymerase chain reaction (RT-PCR) targeting the hypervariable region (HVR) of VP2. Based on the HVR sequences, five isolates (IBS536/2017, IBS624/2017, UPM766/2018, UPM1056/2018, and UPM1432/2019) were selected for whole-genome sequencing using the MiSeq platform. The nucleotide and amino acid (aa) sequences were compared with the previously characterized IBDV strains. Deduced aa sequences of VP2HVR revealed seven isolates with 94-99% aa identity to very virulent strains (genogroup 3), two isolates with 97-100% aa identity to variant strains (genogroup 2), and two strains with 100% identity to the vaccine strain (genogroup 1) of IBDV. The phylogenetic analysis also showed that the isolates formed clusters with the respective genogroups. The characteristic motifs 222T, 249K, 286I, and 318D are typical of the variant strain and were observed for UPM1219/2019 and UPM1432/2019. In comparison, very virulent residues such as 222A, 249Q, 286T, and 318G were found for the vvIBDV, except for the UPM1056/2018 strain with a A222T substitution. In addition, the isolate has aa substitutions such as D213N, G254D, S315T, S317R, and A321E that are not commonly found in previously reported vvIBDV strains. Unlike the other vvIBDVs characterized in this study, UPM766/2018 lacks the MLSL aa residues in VP5. The aa tripeptides 145/146/147 (TDN) of VP1 were conserved for the vvIBDV, while a different motif, NED, was observed for the Malaysian variant strain. The phylogenetic tree showed that the IBDV variant clustered with the American and Chinese variant viruses and are highly comparable to the novel Chinese variants, with 99.9% identity. Based on the sequences and phylogenetic analyses, this is the first identification of an IBDV variant being reported in Malaysia. Further research is required to determine the pathogenicity of the IBDV variant and the protective efficacy of the current IBD vaccines being used against the virus.
  9. Akhtar A, Hair-Bejo M, Hussein EA, Zakaria Z
    Vet Med Int, 2021;2021:8818308.
    PMID: 34055283 DOI: 10.1155/2021/8818308
    This study was conducted to inactivate Salmonella enteriditis phage types (SE pt) and to determine the safety and efficacy of inactivated SE pt in chickens. SE pt 1, 3A, 6A, 7, and 35 were inactivated and inoculated (0.20 mL) in 124 chickens divided into 6 groups (CV1, CV3A, CV6A, CV7, CV35, and CV0 as a control). Sampling was conducted on day 14 after inoculation (pi). Eight chickens from each group were separated on day 14 pi for oral challenge with 0.20 mL/chicken (1010 cfu/mL) SE pt 6A and designated CV1C, CV3AC, CV6AC, CV7C, CV35C, and CV0C as control chickens. On days 7 and 14 postchallenge (pc), 4 chickens from every group were sacrificed for sampling. There was no significant difference in the body weight between different groups. In challenged groups, there was no significant association between different tissues and isolation of Salmonella on days 7 and 14 pc. There was significance (p 
  10. Ismail MI, Wei TS, Hair-Bejo M, Omar AR
    Arch Virol, 2020 Dec;165(12):2777-2788.
    PMID: 32964293 DOI: 10.1007/s00705-020-04812-2
    Besides the vaccine strains, the Malaysian variant (MV) and QX-like are the predominant IBVs detected on commercial poultry farms. These two virus strains are distinct based on genomic and pathogenicity studies. In this study, we determined the sequence of the S1 gene and compared the pathogenicity of serial passage 70 (P70) of Malaysian QX-like (QX/P70) and MV (MV/P70) strains with that of their respective wild-type viruses. The nucleotide and amino acid sequences of the complete S1 genes of QX/P70 and MV/P70 showed 1.4 to 1.6% and 3.0 to 3.3% variation, respectively, when compared to the wild-type virus. Most of the mutations were insertions and substitutions in the hypervariable regions (HVRs), primarily in HVR 3. Furthermore, selection pressure analysis showed that both viruses are under purifying selection. A pathogenicity study in specific-pathogen-free (SPF) chickens showed a reduction in respiratory and kidney lesions in chickens inoculated with MV/P70, but not with QX/P70, when compared to the respective wild-type viruses. However, MV/P70 is still pathogenic and can cause ciliary damage. In conclusion, the MV IBV strain is more responsive than the QX-like IBV strain following the attenuation process used for the development of a live attenuated IBV vaccine.
  11. Ismail MI, Tan SW, Hair-Bejo M, Omar AR
    J Vet Sci, 2020 Nov;21(6):e76.
    PMID: 33263227 DOI: 10.4142/jvs.2020.21.e76
    BACKGROUND: The predominant infectious bronchitis virus (IBV) strains detected in chickens in Malaysia are the Malaysian variant (MV) and QX-like, which are associated with respiratory distress, nephropathy, and high mortality. On the other hand, the antigenic relatedness and efficacy of IBV vaccines against these 2 field IBV strains are not well characterized.

    OBJECTIVES: This study aimed to determine the antigen relatedness and efficacy of different IB vaccine strains against a challenge with MV and QX-like strains.

    METHODS: The antigen relatedness and the ability of different IB vaccine strains in conferring protection against MV and QX-like were assessed based on the clinical signs, macroscopic lesions, and ciliary activity.

    RESULTS: The MV strain IBS037A/2014 showed minor antigenic subtype differences with the vaccine virus Mass H120 and 4/91 strains but showed major antigenic subtype differences with the K2 strain. The Malaysian QX-like strain IBS130/2015 showed major antigenic subtype differences with the MV strain IBS037A/2014 and the vaccine strains except for K2. Chickens vaccinated once with Mass (H120) or with non-Mass (4/91 and K2) developed antibody responses with the highest antibody titer detected in the groups vaccinated with H120 and 4/91. The mean ciliary activities of the vaccinated chickens were between 56 to 59% and 48 to 52% in chickens challenged with IBS037A/2014 and IBS130/2015, respectively. The vaccinated and challenged birds showed mild to severe lesions in the lungs and kidneys.

    CONCLUSIONS: Despite the minor antigenic subtype differences, a single inoculation with Mass or non-Mass vaccines could not protect against the MV IBS037A/2014 and QX-like IBS130/2015.

  12. Hussein EA, Hair-Bejo M, Liew PS, Adamu L, Omar AR, Arshad SS, et al.
    Microb Pathog, 2019 Apr;129:195-205.
    PMID: 30738178 DOI: 10.1016/j.micpath.2019.01.049
    Infectious bursal disease is one of an OIE list of notifiable diseases. Chicken is the only host that manifests clinical signs and its pathogenicity is correlated with the distribution of antigens in organs. This study was conducted to determine disease pathogenesis and virus tissue tropism by in situ PCR, immunoperoxidase staining (IPS), and HE staining. Twenty four chickens were infected with very virulent Infectious Bursal Disease Virus (vvIBDV). Fifteen chickens were kept as a control group. Infected chickens were sacrificed at hrs 2, 4, 6, 12, days 1, 2, 4, and 6 post-inoculation (pi). While, control chickens were euthanized on days 0, 1, 2, 4, and 6 pi. Different tissues were collected, fixed in 10% buffered formalin, and processed. At hr 2 pi, virus was detected in intestinal, junction of the proventriculus and gizzard, cecal tonsil, liver, kidney, and bursa of Fabricius. At hr 4 pi, virus reached spleen, and at hr 6 pi, it entered thymus. At hr 12 pi, virus concentration increased in positive tissues. The latest invaded tissue was muscle on day 1 pi. Secondary viraemia occurred during 12-24 h pi. In situ PCR was the most sensitive technique to highlight obscure points of infection in this study.
  13. Hussein EA, Hair-Bejo M, Omar AR, Arshad SS, Hani H, Balakrishnan KN, et al.
    Microb Pathog, 2019 Apr;129:213-223.
    PMID: 30771470 DOI: 10.1016/j.micpath.2019.02.017
    Limited deep studies are available in the field of early stages of pathogenesis of Newcastle disease virus (NDV) infection and tissue tropism of NDV. In this study, 24 specific pathogen free (SPF) chickens of white leghorn breed were infected with Newcastle disease (ND) by intranasal administration of 10⁵ 50% EID50/0.1 mL of velogenic NDV (vNDV). A second group of 15 chickens were kept as a control group. Chickens were monitored every day to record clinical signs. Infected chickens were euthanized by cervical dislocation at successive times, namely at hours (hrs) 2, 4, 6, 12, days 1, 2, 4, and 6 post-inoculation (pi). Whereas, control group chickens were euthanized on days 0, 1, 2, 4, and 6 pi. Tissues of brain, trachea, lung, caecal tonsil, liver, kidney, spleen, heart, proventriculus, intestine, and thymus were collected, fixed in 10% buffered formalin, embedded in paraffin, and sectioned. HS staining, immunoperoxidase staining (IPS) and in situ PCR were applied. It was concluded that at hr 2 pi, virus seemed to be inclined to trachea and respiratory tract. Meanwhile, it attacked caecal tonsils, intestine and bursa of Fabricus. While primary viraemia was ongoing, virus created footing in kidney and thymus. At hr 4 pi, proventriculus, liver, and spleen were attacked. However, at hr 6 pi, brain and heart were involved. Secondary viraemia probably started as early as hr 12 pi since all collected tissues were positive. Tissue tropism was determined in trachea, caecal tonsil, liver, bursa of Fabricius, intestine, proventriculus, lung, spleen, thymus, kidney, heart, and brain.
  14. Jahromi MZ, Bello MB, Abdolmaleki M, Yeap SK, Hair-Bejo M, Omar AR
    Dev Comp Immunol, 2018 10;87:116-123.
    PMID: 29886054 DOI: 10.1016/j.dci.2018.06.004
    To gain insights into the role of CD3-/28.4+ intraepithelial lymphocytes-natural killer (CD3-/28.4+IEL-NK) cells during infectious bursal disease virus (IBDV) infection, characterisation of the cells was performed following infection with different strains of the virus. In vitro treatment with IL-18 or ionomycin/PMA successfully stimulated and activated the cells via a significant increase in the expression of CD69, B-Lec, CHIR-AB1 and NK-lysin. Similarly, chickens infected with the vaccine strain of IBDV also up-regulated the expression of CD69, B-Lec, CHIR-AB1 and NK-lysin in CD3-/28.4+ IEL-NK cells up to 3 days post infection (dpi) and down-regulated the expression of the inhibitory receptor B-NK at 3 dpi. On the contrary, infection with the very virulent IBDV (vvIBDV) strain lead to a reduced activation of the cells by down-regulating the expression of the CD69, CHIR-AB1 and NK-lysin especially at 1 dpi. These findings altogether demonstrate the differential activation of CD3-/28.4+IEL-NK cells in chicken following infection with the vaccine or very virulent strains of IBDV. The study therefore provides an important clue into the differential pathogenesis of IBDV infection in chicken. Further studies are however required to determine the functional importance of these findings during IBDV vaccination and infection.
  15. Farhanah MI, Yasmin AR, Khanh NP, Yeap SK, Hair-Bejo M, Omar AR
    Arch Virol, 2018 Aug;163(8):2085-2097.
    PMID: 29626271 DOI: 10.1007/s00705-018-3841-7
    Very virulent infectious bursal disease virus (vvIBDV) targets B lymphocytes in the bursa of Fabricius (BF), causing immunosuppression and increased mortality rates in young birds. There have been few studies on the host immune response following vvIBDV infection at different inoculum doses in chickens with different genetic backgrounds. In this study, we characterized the immune responses of specific-pathogen-free (SPF) chickens and Malaysian red jungle fowl following infection with vvIBDV strain UPM0081 at 103.8 and 106.8 times the 50% embryo infectious dose (EID50). The viral burden, histopathological changes, immune cell populations, and expression of immune-related genes were measured and compared between infected and uninfected bursa at specific intervals. The populations of KUL1+, CD3+CD4+ and CD3+CD8+ cells were significantly increased in both types of chickens at 3 dpi, and there was significant early depletion of IgM+ B cells at 1 dpi in the red jungle fowl. vvIBDV infection also induced differential expression of genes that are involved in Th1 and pro-inflammatory responses, with groups receiving the higher dose (106.8 EID50) showing earlier expression of IFNG, IL12B, IL15, IL6, CXCLi2, IL28B, and TLR3 at 1 dpi. Although both chicken types showed equal susceptibility to infection, the red jungle fowl were clinically healthier than the SPF chickens despite showing more depletion of IgM+ B cells and failure to induce IFNB activation. In conclusion, high-dose vvIBDV infection caused an intense early host immune response in the infected bursa, with depletion of IgM+ B cells, bursal lesions, and cytokine expression as a response to mitigate the severity of the infection.
  16. Khanh NP, Tan SW, Yeap SK, Lee HJ, Choi KS, Hair-Bejo M, et al.
    J Comp Pathol, 2018 May;161:43-54.
    PMID: 30173857 DOI: 10.1016/j.jcpa.2018.04.006
    Infectious bronchitis viruses (IBVs) circulating in Malaysia are classified into two groups as Malaysian QX-like and variant strains. In this study, the pathogenicity of IBS130/2015 (QX-like) and IBS037A/2014 (variant) IBVs in 1-day-old and 30-day-old specific pathogen free (SPF) chickens was characterized. Both strains caused respiratory and kidney infections based on immunohistochemistry (IHC), real-time quantitative polymerase chain reaction (qPCR) and a ciliostasis study; however, the results showed that the QX-like strain was more pathogenic, caused higher mortality and showed higher tissue tropism for the kidney than the variant strain. In contrast, despite causing low or no mortality depending on the age of the infected chickens, the Malaysian variant strain showed high tissue tropism for the respiratory tract compared with the QX-like strain. IHC and qPCR indicated the presence of both IBV strains in the epithelial lining of villi in the jejunum and the caecal tonsil; however, no pathological changes were detected in these organs. Both the Malaysian QX-like and variant IBV strains are able to infect the respiratory tract and kidney of chickens irrespective of age.
  17. Farhanah MI, Yasmin AR, Mat Isa N, Hair-Bejo M, Ideris A, Powers C, et al.
    J Gen Virol, 2018 Jan;99(1):21-35.
    PMID: 29058656 DOI: 10.1099/jgv.0.000956
    Infectious bursal disease is a highly contagious disease in the poultry industry and causes immunosuppression in chickens. Genome-wide regulations of immune response genes of inbred chickens with different genetic backgrounds, following very virulent infectious bursal disease virus (vvIBDV) infection are poorly characterized. Therefore, this study aims to analyse the bursal tissue transcriptome of six inbred chicken lines 6, 7, 15, N, O and P following infection with vvIBDV strain UK661 using strand-specific next-generation sequencing, by highlighting important genes and pathways involved in the infected chicken during peak infection at 3 days post-infection. All infected chickens succumbed to the infection without major variations among the different lines. However, based on the viral loads and bursal lesion scoring, lines P and 6 can be considered as the most susceptible lines, while lines 15 and N were regarded as the least affected lines. Transcriptome profiling of the bursa identified 4588 genes to be differentially expressed, with 2985 upregulated and 1642 downregulated genes, in which these genes were commonly or uniquely detected in all or several infected lines. Genes that were upregulated are primarily pro-inflammatory cytokines, chemokines and IFN-related. Various genes that are associated with B-cell functions and genes related to apoptosis were downregulated, together with the genes involved in p53 signalling. In conclusion, bursal transcriptome profiles of different inbred lines showed differential expressions of pro-inflammatory cytokines and chemokines, Th1 cytokines, JAK-STAT signalling genes, MAPK signalling genes, and their related pathways following vvIBDV infection.
  18. Hussein EA, Hair-Bejo M, Adamu L, Omar AR, Arshad SS, Awad EA, et al.
    Vet Med Int, 2018;2018:9296520.
    PMID: 30631413 DOI: 10.1155/2018/9296520
    Newcastle disease virus strains are velogenic, mesogenic, and lentogenic. This study aims to design a scoring system for lesions induced by different strains of Newcastle disease virus in chicken. Three experiments were conducted. In experiments 1 and 2, chickens were divided into infected and control groups. Infected groups of experiments 1 and 2 consisted of 6 and 24 specific pathogen-free (SPF) chickens, respectively. Control groups in experiments 1 and 2 consisted of 6 and 15 SPF chickens, respectively. In infected groups, infection was induced by intranasal administration of 105 50% EID50/0.1 mL of velogenic Newcastle disease virus strain (vNDV). Infected chickens in experiment 1 were euthanised by cervical dislocation on days 3, 6, and 7 postinoculation (pi). Infected chickens in experiment 2 were euthanised at hours (hrs) 2, 4, 6, 12 and days 1, 2, 4, and 6 pi. Chickens of the control group in experiment 1 were euthanised on days 3 and 7 pi, whereas control group chickens in experiment 2 were euthanised on days 0, 1, 2, 4, and 6 pi. Then in experiment 3, 15 SPF chickens were divided into three groups; in the first group, 5 SPF chickens were infected with vNDV, in the second group, 5 SPF chickens were infected with lentogenic NDV (lNDV) (103.0 EID50/0.1 mL), and the third group was kept without infection as a control group. Chickens were euthanised on day 5 pi. In all previous experiments, tissues of brain, trachea, lung, caecal tonsil, liver, kidney, spleen, heart, proventriculus, intestine, and thymus were collected, fixed in 10% buffered formalin, embedded in paraffin, and sectioned. HS staining was applied. Tissues were examined under light microscope and changes were recorded. A scoring system was designed for lesions induced by different strains of NDV and, accordingly, lesions were scored. The scoring system was found helpful in the evaluation of disease severity.
  19. Bello MB, Yusoff KM, Ideris A, Hair-Bejo M, Peeters BPH, Jibril AH, et al.
    Adv Virol, 2018;2018:6097291.
    PMID: 30631359 DOI: 10.1155/2018/6097291
    Newcastle disease (ND) is one of the most important avian diseases with considerable threat to the productivity of poultry all over the world. The disease is associated with severe respiratory, gastrointestinal, and neurological lesions in chicken leading to high mortality and several other production related losses. The aetiology of the disease is an avian paramyxovirus type-1 or Newcastle disease virus (NDV), whose isolates are serologically grouped into a single serotype but genetically classified into a total of 19 genotypes, owing to the continuous emergence and evolution of the virus. In Nigeria, molecular characterization of NDV is generally very scanty and majorly focuses on the amplification of the partial F gene for genotype assignment. However, with the introduction of the most objective NDV genotyping criteria which utilize complete fusion protein coding sequences in phylogenetic taxonomy, the enormous genetic diversity of the virus in Nigeria became very conspicuous. In this review, we examine the current ecological distribution of various NDV genotypes in Nigeria based on the available complete fusion protein nucleotide sequences (1662 bp) in the NCBI database. We then discuss the challenges of ND control as a result of the wide genetic distance between the currently circulating NDV isolates and the commonest vaccines used to combat the disease in the country. Finally, we suggest future directions in the war against the economically devastating ND in Nigeria.
  20. Lawal N, Hair-Bejo M, Arshad SS, Omar AR, Ideris A
    J Pathog, 2018;2018:1068758.
    PMID: 30245887 DOI: 10.1155/2018/1068758
    Two Malaysian very virulent infectious bursal disease virus (vvIBDV) strains UPM0081 (also known as B00/81) and UPM190 (also known as UPM04/190) isolated from local IBD outbreaks in 2000 and 2004, respectively, were separately passaged for 12 consecutive times in 11-day-old specific pathogen free (SPF) chicken embryonated eggs (CEE) via the chorioallantoic membrane (CAM) route. The CEE passage 8 (EP8) isolates were passaged once in BGM-70 cell line yielding UPM0081EP8BGMP1 and UPM190EP8BGMP1, while the EP12 isolates were passaged 15 times in BGM-70 cell line yielding UPM0081EP12BGMP15 and UPM190EP12BGMP15 using T25 tissue culture flask. These isolates were all propagated once in bioreactor using cytodex 1 as microcarrier at 3 g per liter (3 g/L) yielding UPM0081EP8BGMP1BP1, UPM190EP8BGMP1BP1, UPM0081EP12BGMP15BP1, and UPM190EP12BGMP15BP1 isolates. The viruses were harvested at 3 days after inoculation, following the appearance of cytopathic effects (CPE) characterized by detachment from the microcarrier using standard protocol and filtered using 0.2 μm syringe filter. The filtrates were positive for IBDV by RT-PCR and immunofluorescence. Sequence and phylogenetic tree analysis indicated that the isolates were of the vvIBDV strains and were not different from the flask propagated parental viruses.
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