Displaying publications 41 - 46 of 46 in total

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  1. Balakrishnan KN, Abdullah AA, Bala JA, Jesse FFA, Abdullah CAC, Noordin MM, et al.
    Infect Genet Evol, 2021 06;90:104783.
    PMID: 33640483 DOI: 10.1016/j.meegid.2021.104783
    OBJECTIVE: This study investigated the suitability of siRNA targeting specific genes that cause inhibition of virus replication in vitro especially for the virus that capable of crossing placenta and we employed a novel transplacental rat cytomegalovirus that mimics infection in human.

    METHODS: Six unique siRNAs with three each targeting different regions of IE2 (ie2a, ie2b and ie2c) and DNA polymerase (dpa, dpb and dpc) were prepared and tested for antiviral activities. The efficacy as an antiviral was determined in in-vitro by measuring TCID50 virus titer, severity of virus-induced cytopathic effect (CPE), intracellular viral genome loads by droplet digital PCR, the degree of apoptosis in siRNA-treated cells and relative expression of viral mRNA in infected Rat Embryo Fibroblast (REF) cells.

    FINDINGS: Remarkably, the siRNAs: dpa, dpb and IE2b, significantly reduced virus yield (approximately >90%) compared to control group at day 18 post infection (p.i). Changes in CPE indicated that DNA polymerase siRNAs were capable of protecting cells against CMV infection at day 14 p.i with higher efficiency than GCV (at the concentration of 300 pmol). Gene expression analysis revealed a marked down regulation of the targeted DNA polymerase gene (73.9%, 96.0% and 90.7% for dpa, dpb and dpc siRNA, respectively) and IE2 gene (50.8%, 49.9% and 15.8% for ie2a, ie2b and ie2c siRNA, respectively) when measured by RT-qPCR. Intracellular viral DNA loads showed a significant reduction for all the DNA polymerase siRNAs (dpa: 96%, dpb: 98% and dpc:92) compared to control group (P 

  2. Bala JA, Balakrishnan KN, Abdullah AA, Adamu L, Noorzahari MSB, May LK, et al.
    BMC Vet Res, 2019 Jul 18;15(1):250.
    PMID: 31319873 DOI: 10.1186/s12917-019-1999-1
    BACKGROUND: Orf virus causes a scabby skin lesions which decreases productivity in small ruminants. The unknown status of this disease in the eastern region of Peninsular Malaysia warrants a study to determine sero-prevalence of orf with regards to farmers' compliance level towards the Herd Health Program (HHP) programme.

    RESULTS: Out of 504 animals, 115 were positive for Orf-virus antibodies. An overall prevalence rate of 22.8% indicated a high prevalence of orf disease in this region. It was observed that 25.1% (92/367) of goats were positive and 16.8% (23/137) of sheep sero-converted for Orf virus antibody. Several factors were measured for their possible association with prevalence of Orf virus infection. The prevalence was higher in LY farm, JC breed, kid and female animals, and in the presence of disease lesion. Chi-square analysis showed a significant association of three risk factors which are species, age and sex of the animals (P  0.05). Farms surveyed usually practised intensive management system, keeping animals in the shade at all time, due to limited availability of suitable land as a free-range grazing area. An interview with small holder farmers revealed a lack of awareness of the main goals of herd health programme. An overall compliance level of 42.7% was observed for all HHP parameters. Among the 14 main components of HHP modules, animal identification had recorded highest compliance level (84.62%) while milking management recorded the least compliance (- 82.69%). That explained why there was a high sporadic prevalence of Orf infection in this region.

    CONCLUSION: Good herd health supervision is a rehearsal target to prevent an outbreak and the spread of diseases thus reduces economic losses among farmers. Therefore, a good herd health programme should be in place, in order to prevent and control disease transmission as well as to improve herd immunity.

  3. Pham TH, Rahaman NYA, Lila MAM, Lai HLT, Nguyen LT, Van Nguyen G, et al.
    BMC Vet Res, 2021 Mar 08;17(1):115.
    PMID: 33685458 DOI: 10.1186/s12917-021-02777-1
    BACKGROUND: After a decade of silence, an outbreak of the contagious and Asian endemic disease, goat pox re-emerged in North Vietnam affecting more than 1800 heads with a mortality rate of 6.5%. The inevitable impact of goat pox on hide quality, breeding, chevon and milk production has resulted in a significant economic losses to the developing goat industry of Vietnam. In the act of establishing an effective control of this devastating disease, tracing the source of re-emergence via a phylogenetic study was carried out to reveal their genetic relatedness. Either skin scab or papule from the six affected provinces were collected, cultured into Vero cells followed by restricted enzyme digestion of targeted P32 gene DNA encoding. The P32 gene was then cloned and transformed into E.coli competent cells for further sequencing.

    RESULTS: The isolated sequence is deposited into GenBank under Accession No. MN317561/VNUAGTP1. The phylogenetic tree revealed high similarity of nucleotide and amino acid sequences to references goat pox strains accounting for 99.6 and 99.3, respectively. The Vietnamese strain is clustered together with currently circulating goat pox virus in China, India and Pakistan which suggested the origin of South China.

    CONCLUSIONS: This Vietnam isolate is clustered together with other Asian goat pox strains indicating the dissemination of a common goat pox virus within this continent.

  4. Bala JA, Balakrishnan KN, Abdullah AA, Kimmy T, Abba Y, Bin Mohamed R, et al.
    J Pathog, 2018;2018:9207576.
    PMID: 30155311 DOI: 10.1155/2018/9207576
    Orf is a clinical manifestation of parapoxvirus infection often fatal in goats and sheep especially when they are under stress or influenced by unfavorable environment. This study investigated the pathogenicity of two Orf virus isolates (ORFV UPM1/14 and UPM2/14) and host response in mouse model by using different inoculation sites with/without prior exposure to dexamethasone. Treatments with dexamethasone served as an immunosuppressant that may mimic stress situation in affected animals. Groups of five mice were given intradermal injection of 0.2 mL of tissue culture infective dose 50 (TCID50) of UPM1/14 (Group 1) and UPM2/14 (Group 2) at the dorsum (Group 1A; Group 2A), ear pinna (Group 1B; Group 2B), and labial commissure (Group 1C; Group 2C). An inoculum 0.2 mL of UPM1/14 was administered to animals treated with dexamethasone (n=5; 5 mg/kg/day intraperitoneally) and nondexamethasone (n=5) groups at the dorsum, ear pinna, and labial commissure. No significant difference (p>0.05) was observed in the mean lesion scores among the groups of different inoculation sites or between dexamethasone-treated and nontreated groups. However, there was a significant difference (p<0.05) in the mean stratum thickness of affected skin following inoculation with UPM2/14 isolate at the ear pinna and labial commissure. Histopathology examination revealed keratosis, acanthosis, and ballooning degeneration in the skin of affected mice. Orf virus DNA was detected in the skin samples by targeting F1L and B2L virus-specific genes in polymerase chain reaction (PCR) assay. Intradermal inoculation with UPM1/14 or UPM2/14 isolate produced a mild skin lesion in mice, and there was no significant difference in orf disease manifestation despite variation of inoculation sites. Similarly, short-term dexamethasone administration gave no adverse effects on pathogenicity of orf virus isolates.
  5. Bala JA, Balakrishnan KN, Jesse FFA, Abdullah AA, Noorzahari MSB, Ghazali MT, et al.
    Infect Genet Evol, 2020 01;77:104076.
    PMID: 31678648 DOI: 10.1016/j.meegid.2019.104076
    There is a little information on the characterization of Orf virus strains that are endemic in Malaysia. The relationship between the severity of disease and the molecular genetic profile of Orf virus strains has not been fully elucidated. This study documented the first confirmed report of contagious ecthyma causing by Orf virus in goats from a selected state of eastern peninsular Malaysia. The disease causes significant debilitation due to the inability of affected animals to suckle which brings a great economic loss to the farmers. A total of 504 animals were examined individually to recognize the affected animals with Orf lesion. Skin scrapping was used to collect the scab material from the infected animals. The presence of Orf virus was confirmed by combination of methods including virus isolation on vero cells, identification by Transmission Electron Microscopy (TEM) and molecular technique using PCR and Sanger sequencing. The results showed the successful isolation of four Orf virus strains with a typical cytopathic effects on the cultured vero cells line. The morphology was confirmed to be Orf virus with a distinctive ovoid and criss cross structure. The phylogenetic analysis revealed that these isolated strains were closely related to each other and to other previously isolated Malaysian orf viruses. In addition these Orf virus strains were closely related to Orf viruses from China and India. This study provides more valuable insight in terms of genotype of Orf virus circulating in Malaysia.
  6. Balakrishnan KN, Abdullah AA, Camalxaman SN, Quah YW, Abba Y, Hani H, et al.
    Genome Announc, 2015;3(3).
    PMID: 26044413 DOI: 10.1128/genomeA.00451-15
    The complete genome sequence of the ALL-03 strain of rat cytomegalovirus (RCMV) has been determined. The RCMV genome has a length of 197,958 bp and is arranged as a single unique sequence flanked by 504-bp terminal direct repeats. This strain is closely related to the English strain of RCMV in terms of genetic arrangement but differs slightly in size.
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