1.Molecular characterization and phylogenetic analysis of avian influenza H3N8 virus isolated from imported waterfowl in Malaysia
Leow, B.L. ; Shohaimi, S.A. ; Mohd. Yusop, F.F. ; Sidik, M.R. ; Mohd Saeid, F.H.
Tropical Biomedicine 2023;40(No.2):220-235
Wild aquatic birds are natural reservoirs of influenza A viruses and H3 subtype is one of the most
prevalent subtypes in waterfowl. Two H3N8 viruses of low pathogenic avian influenza (LPAI) were
isolated via egg inoculation technique from the fecal swab specimens from imported barnacle goose
and paradise shelduck in Veterinary Research Institute Ipoh, Malaysia. The full length of eight gene
segments of the two viruses were amplified and sequenced with specific primers. The sequences were
molecularly characterized, and the sequence identity were assessed with other published sequences.
The two viruses are identical and they possess the same amino acid sequences for all the eight gene
segments. The viruses were highly similar to the H3 virus from Netherlands and N8 virus from Belgium
respectively. Phylogenetic analysis revealed that all the eight gene segments were grouped in the
Eurasian lineage, and genetic reassortment may occur between the internal genes of the H3 viruses
and other AI subtypes. Though four amino acid substitutions were identified in the hemagglutinin gene,
the viruses retained most of the avian-type receptor binding preference. Few amino acid substitutions
were observed in all internal genes. Most of the neuraminidase inhibitors and adamantine resistance
related mutation were not seen in the viruses. The replicative capacity, cross species transmissibility,
and potential zoonotic risk of the viruses are worth further investigation. As H3 virus poses potential
threats to both human and animals, and with the increase in the international trade of birds; strict
quarantine practice at the entry point and good laboratory diagnostic capabilities is crucial to prevent
the introduction of new AI virus into our country.
2.Isolation and phylogenetic analysis of avian infectious bronchitis virus from an imported chicken meat product in Malaysia
Leow, B.L. ; Shohaimi, S.A. ; Mohd. Yusop, F.F. ; Sidik, M.R. ; Mohd. Saeid, F.H.
Tropical Biomedicine 2024;41(No.1):29-35
Avian infectious bronchitis (IB), a Gammacoronavirus, is a highly contagious upper respiratory disease,
affecting chickens of all ages with a significant economic threat to the poultry industry. In February 2020,
a specimen of imported chicken meat product was received and requested for coronavirus testing. The
result was positive for the avian coronavirus, the IB virus (IBV) by molecular detection in the pre-screening
test. Thus, this study aimed to isolate and characterize the IBV from the specimen. Virus isolation via
egg inoculation was attempted and IBV was successfully isolated. The S1 subunit of the spike (S) gene of
the IBV was amplified, sequenced, and the Basic Local Alignment Search Tool (BLAST) analysis showed
that the IBV has 99% and 98% nucleotide similarity with the Malaysian and China IBVs, respectively. The
phylogenetic analysis indicated that the virus belongs to the GI-19 lineage (also known as the QX strain)
and is grouped with other IBVs from Malaysia and China. The GI-19 lineage is one of the primary IB
strains that circulate in Malaysia. The recovery of the virus may be due to the persistence characteristic
of the virus on meat; and the cold chain practices in the imported food product prolong the survival
of this coronavirus. Though IBV is not identified as a hazard in chicken meat or meat products, raw
food should be cooked thoroughly before being consumed. With the increase in international trade in
poultry and poultry products, disease screening at the entry point and import risk analysis is crucial to
ensure food safety and prevent the introduction of new viruses into Malaysia.