We isolated novel reassortant avian influenza A(H5N6) viruses containing genes from clade 2.3.4.
View Article and Find Full Text PDFThe winter of 2020-2021 in South Korea witnessed severe outbreaks of Highly Pathogenic Avian Influenza (HPAI) viruses, specifically multiple genotypes of the H5N8 subtype. These outbreaks prompted an extensive investigation into the genetic characteristics and evolutionary dynamics of these viruses. Under the auspices of the National Institute of Wildlife Disease Control and Prevention (NIWDC), we conducted a nationwide surveillance program, collecting 7588 specimens from diverse wild bird habitats.
View Article and Find Full Text PDFDuring October 2022-March 2023, highly pathogenic avian influenza (HPAI) A(H5N1) clade 2.3.4.
View Article and Find Full Text PDFHuman infection by avian-origin subtype H10 influenza viruses has raised concerns about the pandemic potential of these microbes. H10 subtype low pathogenic avian influenza viruses (LPAIVs) have been isolated from wild birds and poultry worldwide. Here, we isolated 36 H10 LPAIVs from wild bird habitats (a mean annual rate of 3.
View Article and Find Full Text PDFThe first human case of zoonotic A(H7N4) avian influenza virus (AIV) infection was reported in early 2018 in China. Two months after this case, novel A(H7N4) viruses phylogenetically related to the Jiangsu isolate emerged in ducks from live bird markets in Cambodia. During active surveillance in Cambodia, a novel A(H7N6) reassortant of the zoonotic low pathogenic AIV (LPAIV) A(H7N4) was detected in domestic ducks at a slaughterhouse.
View Article and Find Full Text PDFBackground: South Korea conducts annual national surveillance programs to detect avian influenza (AI) in domestic poultry, live bird markets, and wild birds. In March 2017, an AIV was isolated from fecal samples in an outdoor aviary flight cage in a zoo in Korea.
Results: Nucleotide sequencing identified the isolate as low pathogenic avian influenza virus (LPAIV) H7N7, and DNA barcoding analysis identified the host species as red-crowned crane.
Since 2004, several outbreaks of highly pathogenic avian influenza (HPAI) have been reported in Cambodia. Until 2013, all H5N1 viruses identified in Cambodia belonged to clade 1 and its subclades. H5N1 HPAI viruses belonging to clade 2.
View Article and Find Full Text PDFH5 and H7 subtypes of low pathogenic avian influenza viruses (LPAIVs) can mutate to highly pathogenic forms and are therefore subject to stringent controls. We characterized H5 LPAIVs isolated from wild-bird habitats and duck farms in South Korea from 2010 to 2017. Through nationwide active surveillance for AIVs, 59 H5 LPAIVs were isolated from wild-bird habitats (a mean annual rate of 5.
View Article and Find Full Text PDFSince 2004, there have been multiple outbreaks of H5 highly pathogenic avian influenza (HPAI) viruses in Laos. Here, we isolated H5N1 HPAI viruses from poultry outbreaks in Laos during 2015-2018 and investigated their genetic characteristics and pathogenicity in chickens. Phylogenetic analysis revealed that the isolates belonged to clade 2.
View Article and Find Full Text PDFIn this study, we demonstrate a novel mechanism for hemagglutinin (HA) activation in a naturally occurring H7N6 avian influenza A virus strain, A/mallard duck/Korea/6L/2007 (A/Mdk/6L/07). This novel mechanism allows for systemic infection of chickens, ducks, and mice, and A/Mdk/6L/07 can replicate without exogenous trypsin and exhibits broad tissue tropism in animals despite the presence of a monobasic HA cleavage motif (PEIPKGR/G). The trypsin-independent growth phenotype requires the N6 neuraminidase and the specific recognition of glycine at the P2 position of the HA cleavage motif by a thrombin-like protease.
View Article and Find Full Text PDFBackground: In addition to seasonal influenza viruses recently circulating in humans, avian influenza viruses (AIVs) of H5N1, H5N6 and H7N9 subtypes have also emerged and demonstrated human infection abilities with high mortality rates. Although influenza viral infections are usually diagnosed using viral isolation and serological/molecular analyses, the cost, accessibility, and availability of these methods may limit their utility in various settings. The objective of this study was to develop and optimized a multiplex detection system for most influenza viruses currently infecting humans.
View Article and Find Full Text PDFSevere fever with thrombocytopenia syndrome phlebovirus (SFTSV) has a wide host range. Not only has it been found in humans, but also in many wild and domesticated animals. The infection of breeding deer on farms is a particularly worrisome public health concern due to the large amount of human contact and the diverse use of deer products, including raw blood.
View Article and Find Full Text PDFThe reverse genetics (RG) system of influenza A viruses is well established. However, the conventional sequence-dependent method for cloning influenza genome segments is time-consuming and requires multiple processes (eg. enzyme digestion and ligation) and exhibits low cloning efficiency compared to the sequence-independent cloning method.
View Article and Find Full Text PDFSevere fever with thrombocytopenia syndrome phlebovirus (SFTSV), listed in the most dangerous pathogens by the World Health Organization, has 12-30% fatality rates with a characteristic thrombocytopenia syndrome. With a majority of clinically diagnosed SFTSV patients older than ~50 years of age, age is a critical risk factor for SFTSV morbidity and mortality. Here, we report an age-dependent ferret model of SFTSV infection and pathogenesis that fully recapitulates the clinical manifestations of human infections.
View Article and Find Full Text PDFBecause H5N1 influenza viruses continuously threaten the public health, the WHO has prepared various clades of H5N1 mock-up vaccines as one of the measures for pandemic preparedness. The recent worldwide outbreak of H5Nx virus which belongs to clade 2.3.
View Article and Find Full Text PDFSevere fever with thrombocytopenia syndrome (SFTS) is a newly emerging tick-borne infectious disease caused by the SFTS virus (SFTSV). To investigate the prevalence of SFTSV in domestic goats in South Korea, we collected blood samples in commercial slaughterhouses in Chungbuk Province in 2017. Of the 207 samples tested, 4 (2%) were found to be positive for viral RNA by RT-PCR and 30 (14.
View Article and Find Full Text PDFAs shown during the 2009 pandemic H1N1 (A(H1N1)pdm09) outbreak, egg-based influenza vaccine production technology is insufficient to meet global demands during an influenza pandemic. Therefore, there is a need to adapt cell culture-derived vaccine technology using suspended cell lines for more rapid and larger-scale vaccine production. In this study, we attempted to generate a high-growth influenza vaccine strain in MDCK cells using an A/Puerto/8/1934 (H1N1) vaccine seed strain.
View Article and Find Full Text PDFHighly pathogenic avian influenza (HPAI) A(H5N6) and A(H5N8) virus infections resulted in the culling of more than 37 million poultry in the Republic of Korea during the 2016/17 winter season. Here we characterize two representative viruses, A/Environment/Korea/W541/2016 [Em/W541(H5N6)] and A/Common Teal/Korea/W555/2017 [CT/W555(H5N8)], and evaluate their zoonotic potential in various animal models. Both Em/W541(H5N6) and CT /W555(H5N8) are novel reassortants derived from various gene pools of wild bird viruses present in migratory waterfowl arising from eastern China.
View Article and Find Full Text PDFRecent canine influenza outbreaks have raised concerns about the generation of pathogenic variants that may pose a threat to public health. Here, we examine avian-like H3N2 canine influenza viruses (CIVs) isolated from 2009 to 2013 in South Korea from dogs. Phylogenetic analysis revealed that these viruses are closely related to strains previously isolated from dogs in Korea and China.
View Article and Find Full Text PDFWe investigated influenza A(H5N6) viruses from migratory birds in Chungnam and Gyeonggi Provinces, South Korea following a reported die-off of poultry in nearby provinces in November 2017. Genetic analysis and virulence studies in chickens and ducks identified our isolate from December 2017 as a novel highly pathogenic avian influenza virus. It resulted from reassortment between the highly virulent H5N8 strain from Korea with the N6 gene from a low-pathogenic H3N6 virus from the Netherlands.
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