Three isolates of Infectious bursal disease virus (IBDV), designated UPM04178, UPM04190 and UPM04238, were obtained from severe outbreaks of infectious bursal disease (IBD) in Malaysia in 2004. The hypervariable region (HPVR) of VP2 gene of these isolates was sequenced. The obtained sequences were compared with those of other isolates. The highest similarity (98%) concerning both nucleotide and amino acid sequences was found to very virulent IBDV (vvIBDV) strains. Phylogenetic analysis revealed clustering of the three isolates with vvIBDV strains. Evolutionary relatedness of the three isolates to vvIBDV strains was demonstrated by three phylogenetic methods: bootstrap values of 100%, 95% and 90% for nucleotide sequences and those of 58%, 86% and 96% for amino acid sequences were obtained by the distance, maximum parsimony and maximum likehood methods, respectively. It is concluded that UPM04178, UPM04190 and UPM04238 are vvIBDV isolates of serotype 1, which originate from a common ancestor of IBDV strains present in Malaysia.
The immunochromatographic assay is an alternative method for simple and rapid detection of Infectious bursal disease virus (IBDV) in chickens using colloidal gold-antibody conjugate. The whole-virus antigen of IBDV (UPM04190 isolate) and the high-affinity polyclonal antibodies directed against IBDV were blotted onto nitrocellulose membranes for test and control lines, respectively. Evaluation of the strip was performed using serum samples from experimentally and naturally infected chickens. The results showed that the test strip was more sensitive than the commercial enzyme-linked immunosorbent assay (ELISA) because it could detect a dilution factor up to 120,000 (250 ELISA units) for positive samples. It was also specific, in that it detected IBDV antibodies and did not cross-react with antibodies to other chicken viruses. The method was rapid (2 min) in both clinical and field environments with samples needing only a minimum amount (50 µl) of blood to produce an acceptable detection signal. The pen-site test strip proved successful in monitoring the immune status of chickens against the IBDV infection.
Countries around the world are gearing for the transition of the coronavirus disease 2019 (COVID-19) from pandemic to endemic phase but the emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants could lead to a prolonged pandemic. SARS-CoV-2 has continued to evolve as it optimizes its adaptation to the human host and the successive waves of COVID-19 have been linked to the explosion of particular variant of concern. As the genetic diversity and epidemiological landscape of SARS-CoV-2 differ from country to country, this study aims to provide insights into the variants that are circulating in Malaysia. Whole genome sequencing was performed for 204 SARS-CoV-2 from COVID-19 cases and an additional 18,667 SARS-CoV-2 genome sequences were retrieved from the GISAID EpiCoV database for clade, lineage and genetic variation analyses. Complete genome sequences with high coverage were then used for phylogeny investigation and the resulting phylogenetic tree was constructed from 8,716 sequences. We found that the different waves of COVID-19 in Malaysia were dominated by different clades with the L and O clade for first and second wave, respectively, whereas the progressive replacement by G, GH, and GK of the GRA clade were observed in the subsequence waves. Continuous monitoring of the genetic diversity of SARS-CoV-2 is important to identify the emergence and dominance of new variant in different locality so that the appropriate countermeasures can be taken to effectively contain the spread of SARS-CoV-2.