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.
Background: Human coronaviruses (HCoVs) are common etiological agents of acute respiratory tract infections. However their prevalence and clinical presentations are less well studied.Methods: Here in Singapore, we conducted acute respiratory infection surveillance in selected military camps to investigate the epidemiology of such infections and pathogens involved. Nasal washes were done for patients that meet the case criteria along with a survey questionaire. Nucleic acids were then extracted from the nasal washes and subjected to molecular testing for presence of various pathogens, including human coronaviruses.Results: The results presented will focus on the four human coronaviruses 229E, HKU1, NL63 and OC43 detected over a 2 ½ year period of surveillance.Conclusion: The epidemiology of the four human coronaviruses 229E, HKU1, NL63 and OC43 over the 2 ½ year period and how they compare with that of other published studies will be discussed. http://dx.
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