title: Molecular characterization of low pathogenic avian influenza viruses, isolated from food products imported into Singapore.
abstract: We have completed the genetic characterization of all eight gene segments for four low pathogenic avian influenza (LPAI) viruses. The objective of this study was to detect the presence of novel signatures that may serve as early warning indicators of the conversion of LPAI viruses to high pathogenic avian influenza (HPAI) viruses. This study included three H5N2 and one H5N3 viruses that were isolated from live poultry imported into Singapore as part of the national avian influenza virus (AIV) surveillance program. Based on the molecular criterion of the World Organisation for Animal Health (OIE), sequence analysis with the translated amino acid (aa) sequence of the hemagglutinin (HA) gene revealed the absence of multibasic aa at the HA cleavage site, identifying all four virus isolates as LPAI. Detailed phylogenetic tree analyses using the HA and neuraminidase (NA) genes clustered these isolates in the Eurasian H5 lineage, but away from the HPAI H5 subtypes. This analysis further revealed that the internal genes clustered to different avian and swine subtypes, suggesting that the four isolates may possibly share their ancestry with these different influenza subtypes. Our results suggest that the four LPAI isolates in this study contained mainly avian signatures, and the phylogenetic tree for the internal genes further suggests the potential for reassortment with other different circulating avian subtypes. This is the first comprehensive report on the genetic characterization of LPAI H5N2/3 viruses isolated in South-East Asia.
authors.affiliation: Detection and Diagnostics Laboratory, DSO National Laboratories, Singapore, Singapore.
authors.forename: Dawn Su-Yin
authors.initials: DS
authors.lastname: Yeo
authors.forename: Sock-Hoon
authors.initials: SH
authors.lastname: Ng
authors.forename: Chin-Wen
authors.initials: CW
authors.lastname: Liaw
authors.forename: Ley-Moy
authors.initials: LM
authors.lastname: Ng
authors.forename: Eugene Jing-Hui
authors.initials: EJ
authors.lastname: Wee
authors.forename: Elizabeth Ai-Sim
authors.initials: EA
authors.lastname: Lim
authors.forename: Shirely Lay-Kheng
authors.initials: SL
authors.lastname: Seah
authors.forename: Wai-Kwan
authors.initials: WK
authors.lastname: Wong
authors.forename: Chee-Wee
authors.initials: CW
authors.lastname: Lim
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Sugrue
authors.forename: Boon-Huan
authors.initials: BH
authors.lastname: Tan
mesh_terms: D000818:Animals; D003132:Commerce; D005516:Food Microbiology; D009980:Influenza A virus / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D005585:Influenza in Birds / Q000453:epidemiology / Q000821:virology*; D008958:Models, Molecular; D009439:Neuraminidase / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D011159:Population Surveillance; D011200:Poultry; D011487:Protein Conformation; D012846:Singapore / Q000453:epidemiology
chemical_list: D009439:Neuraminidase