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Robert G. Webster - One of the best experts on this subject based on the ideXlab platform.

  • updating the influenza virus library at hokkaido university it s potential for the use of pandemic vaccine strain candidates and diagnosis
    Virology, 2021
    Co-Authors: Naoki Nomura, Yoshihiro Sakoda, Robert G. Webster, Keita Matsuno, Masashi Shingai, Marumi Ohno, Toshiki Sekiya, Ryosuke Omori, Hiroshi Kida
    Abstract:

    Abstract Genetic Reassortment of influenza A viruses through cross-species transmission contributes to the generation of pandemic influenza viruses. To provide information on the ecology of influenza viruses, we have been conducting a global surveillance of zoonotic influenza and establishing an influenza virus library. Of 4580 influenza virus strains in the library, 3891 have been isolated from over 70 different bird species. The remaining 689 strains were isolated from humans, pigs, horses, seal, whale, and the environment. PhyloGenetic analyses of the HA genes of the library isolates demonstrate that the library strains are distributed to all major known clusters of the H1, H2 and H3 subtypes of HA genes that are prevalent in humans. Since past pandemic influenza viruses are most likely Genetic reassortants of zoonotic and seasonal influenza viruses, a vast collection of influenza A virus strains from various hosts should be useful for vaccine preparation and diagnosis for future pandemics.

  • cocirculation of avian h9n2 and contemporary human h3n2 influenza a viruses in pigs in southeastern china potential for Genetic Reassortment
    Journal of Virology, 2001
    Co-Authors: J S M Peiris, Robert G. Webster, Yi Guan, D Markwell, P Ghose, K F Shortridge
    Abstract:

    Pigs are permissive to both human and avian influenza viruses and have been proposed to be an intermediate host for the genesis of pandemic influenza viruses through Reassortment or adaptation of avian viruses. Prospective virological surveillance carried out between March 1998 and June 2000 in Hong Kong, Special Administrative Region, People's Republic of China, on pigs imported from southeastern China, provides the first evidence of interspecies transmission of avian H9N2 viruses to pigs and documents their cocirculation with contemporary human H3N2 (A/Sydney/5/97-like, Sydney97-like) viruses. All gene segments of the porcine H9N2 viruses were closely related to viruses similar to chicken/Beijing/1/94 (H9N2), duck/Hong Kong/Y280/97 (H9N2), and the descendants of the latter virus lineage. PhyloGenetic analysis suggested that repeated interspecies transmission events had occurred from the avian host to pigs. The Sydney97-like (H3N2) viruses isolated from pigs were related closely to contemporary human H3N2 viruses in all gene segments and had not undergone Genetic Reassortment. Cocirculation of avian H9N2 and human H3N2 viruses in pigs provides an opportunity for Genetic Reassortment leading to the emergence of viruses with pandemic potential.

  • Genetic Reassortment of avian swine and human influenza a viruses in american pigs
    Journal of Virology, 1999
    Co-Authors: Nan Nan Zhou, Kurt Rossow, Kyoungjin Yoon, Scott Krauss, Dennis A Senne, John Landgraf, Sabrina L Swenson, Gene Erickson, Lin Liu, Robert G. Webster
    Abstract:

    In late summer through early winter of 1998, there were several outbreaks of respiratory disease in the swine herds of North Carolina, Texas, Minnesota, and Iowa. Four viral isolates from outbreaks in different states were analyzed Genetically. Genotyping and phyloGenetic analyses demonstrated that the four swine viruses had emerged through two different pathways. The North Carolina isolate is the product of Genetic Reassortment between H3N2 human and classic swine H1N1 influenza viruses, while the others arose from Reassortment of human H3N2, classic swine H1N1, and avian viral genes. The hemagglutinin genes of the four isolates were all derived from the human H3N2 virus circulating in 1995. It remains to be determined if either of these recently emerged viruses will become established in the pigs in North America and whether they will become an economic burden.

  • molecular basis for the generation in pigs of influenza a viruses with pandemic potential
    Journal of Virology, 1998
    Co-Authors: Toshihiro Ito, Nelson J S S Couceiro, Sorge Kelm, Linda G Baum, Scott Krauss, Maria R Castrucci, Isabella Donatelli, Hiroshi Kida, James C Paulson, Robert G. Webster
    Abstract:

    Genetic and biologic observations suggest that pigs may serve as “mixing vessels” for the generation of human-avian influenza A virus reassortants, similar to those responsible for the 1957 and 1968 pandemics. Here we demonstrate a structural basis for this hypothesis. Cell surface receptors for both human and avian influenza viruses were identified in the pig trachea, providing a milieu conducive to viral replication and Genetic Reassortment. Surprisingly, with continued replication, some avian-like swine viruses acquired the ability to recognize human virus receptors, raising the possibility of their direct transmission to human populations. These findings help to explain the emergence of pandemic influenza viruses and support the need for continued surveillance of swine for viruses carrying avian virus genes.

  • an epidemiological study of influenza viruses among chinese farm families with household ducks and pigs
    Epidemiology and Infection, 1996
    Co-Authors: N Zhou, G. B. Sharp, S Q He, T Zhang, Robert G. Webster
    Abstract:

    To examine the possibility of interspecies transmission and Genetic Reassortment of influenza viruses on farms in Southern China, we surveyed 20 farm families living outside the city of Nanchang who raised pigs and ducks in their homes. Weekly interviews of family members and virus isolation studies of throat swabs and faecal samples, collected from September 1992 to September 1993, established the seasonal pattern of respiratory tract infections in these families and identified 11 influenza viruses (6 in humans and 5 in ducks). Most of the human isolates were type A of H3N2 subtype. Serologic studies of farm pigs indicated infection by the same human viruses circulating in family members, but there was no evidence that either swine or avian viruses had been transmitted to pigs. Eight of 156 human serum samples inhibited the neuraminidase activity of two of the duck isolates, raising the possibility of interspecies transmission of these avian viruses. Genotype analysis of duck and human isolates provided no evidence for Reassortment. Our findings support the concept that intermingling of humans, pigs and ducks on Chinese farms is favourable to the generation of new, potentially hazardous strains of influenza virus.

Weifeng Shi - One of the best experts on this subject based on the ideXlab platform.

  • the first imported case of rift valley fever in china reveals a Genetic Reassortment of different viral lineages
    Emerging microbes & infections, 2017
    Co-Authors: Jingyuan Liu, Weifeng Shi, Yulan Sun, Shuguang Tan, Yang Pan, Shujuan Cui, Qingchao Zhang, Xiangfeng Dou, Lijuan Chen, Chuansong Quan
    Abstract:

    The first imported case of Rift Valley fever in China reveals a Genetic Reassortment of different viral lineages

  • the first imported case of rift valley fever in china reveals a Genetic Reassortment of different viral lineages
    Emerging microbes & infections, 2017
    Co-Authors: Jingyuan Liu, Weifeng Shi, Yulan Sun, Shuguang Tan, Yang Pan, Shujuan Cui, Qingchao Zhang, Xiangfeng Dou, Lijuan Chen, Chuansong Quan
    Abstract:

    We report the first imported case of Rift Valley fever (RVF) in China. The patient returned from Angola, a non-epidemic country, with an infection of a new reassortant from different lineages of Ri...

  • high Genetic diversity and frequent Genetic Reassortment of avian influenza a h9n2 viruses along the east asian australian migratory flyway
    Infection Genetics and Evolution, 2016
    Co-Authors: Haiming Wang, Zhenjie Zhang, Zhanqiang Chen, Yanru Zhang, Yigang Tong, Michael J Carr, Shuhong Sun, Weifeng Shi
    Abstract:

    To understand the molecular epidemiology and evolution of avian influenza viruses (AIV) along the East Asian-Australian migration flyway, we collected faecal samples (n=2859) between November 2014 and March 2015 from poultry, environmental sources and wild birds in Dongying, Shandong province and Yancheng, Jiangsu province in eastern China. The presence of AIV RNA was evaluated by real-time PCR and the positivity rate ranged from 0 to 29.3%. In both Dongying and Yancheng, samples collected from live poultry markets had the highest positivity rate for AIV RNA. AIV whole genomes were generated and phyloGenetically analysed. Our results demonstrate that most of the viruses belonged to the H9N2 subtype, and could be classified into nine novel genotypes based on the phyloGenetic analysis of the eight gene segments of the AIV genomes. This revealed a high Genetic diversity of H9N2 in this region and suggested that they might have undergone frequent Genetic Reassortment. In addition, the internal genes (PB2, etc.) of two viruses from wild birds and several viruses from poultry belonged to the same gene constellation, suggesting a potential inter-host transmission of AIV between wild birds and poultry in live markets along routes of migratory flyways. Our results highlight the high Genetic diversity of AIV along the East Asian-Australian migration flyway and the need for more extensive AIV surveillance in eastern China.

  • prospective of genomics in revealing transmission Reassortment and evolution of wildlife borne avian influenza a h5n1 viruses
    Current Genomics, 2011
    Co-Authors: Fumin Lei, Weifeng Shi
    Abstract:

    The outbreak of highly pathogenic avian influenza (HPAI) H5N1 disease has led to significant loss of poultry and wild life and case fatality rates in humans of 60%. Wild birds are natural hosts for all avian influenza virus subtypes and over120 bird species have been reported with evidence of H5N1 infection. Influenza A viruses possess a segmented RNA genome and are characterized by frequently occurring Genetic Reassortment events, which play a very important role in virus evolution and the spread of novel gene constellations in immunologically naive human and animal populations. PhyloGenetic analysis of whole genome or sub-genomic sequences is a standard means for delineating Genetic variation, novel Reassortment events, and surveillance to trace the global transmission pathways. In this paper, special emphasis is given to the transmission and circulation of H5N1 among wild life populations, and to the Reassortment events that are associated with inter-host transmission of the H5N1 viruses when they infect different hosts, such as birds, pigs and humans. In addition, we review the inter-subtype Reassortment of the viral segments encoding inner proteins between the H5N1 viruses and viruses of other subtypes, such as H9N2 and H6N1. Finally, we highlight the usefulness of genomic sequences in molecular epidemiological analysis of HPAI H5N1 and the technical limitations in existing analytical methods that hinder them from playing a greater role in virological research.

Yi Guan - One of the best experts on this subject based on the ideXlab platform.

  • genesis of a highly pathogenic and potentially pandemic h5n1 influenza virus in eastern asia
    Nature, 2004
    Co-Authors: Yi Guan, Jia Wang, Gavin J D Smith, Lian Duan, A P Rahardjo, Pilaipan Puthavathana
    Abstract:

    A highly pathogenic avian influenza virus, H5N1, caused disease outbreaks in poultry in China and seven other east Asian countries between late 2003 and early 2004; the same virus was fatal to humans in Thailand and Vietnam1. Here we demonstrate a series of Genetic Reassortment events traceable to the precursor of the H5N1 viruses that caused the initial human outbreak in Hong Kong in 1997 (refs 2–4) and subsequent avian outbreaks in 2001 and 2002 (refs 5, 6). These events gave rise to a dominant H5N1 genotype (Z) in chickens and ducks that was responsible for the regional outbreak in 2003–04. Our findings indicate that domestic ducks in southern China had a central role in the generation and maintenance of this virus, and that wild birds may have contributed to the increasingly wide spread of the virus in Asia. Our results suggest that H5N1 viruses with pandemic potential have become endemic in the region and are not easily eradicable. These developments pose a threat to public and veterinary health in the region and potentially the world, and suggest that long-term control measures are required.

  • h5n1 influenza viruses isolated from geese in southeastern china evidence for Genetic Reassortment and interspecies transmission to ducks
    Virology, 2002
    Co-Authors: Yi Guan, Malik Peiris, K F Kong, K C Dyrting, T M Ellis, T Sit, L J Zhang, K F Shortridge
    Abstract:

    The H5N1 viruses (H5N1/97) associated with the "bird-flu" incident in the Hong Kong SAR have not been isolated since the slaughter of poultry in December 1997 brought that outbreak to an end. Recent evidence points to this virus as having arisen through a Reassortment of a number of precursor avian viruses and a virus related to Goose/Guangdong/1/96 (H5N1) (Gs/Gd/96) was the likely donor of the H5 hemagglutinin. We characterize the Goose/Guangdong/1/96-like viruses isolated from geese and ducks imported into Hong Kong in the year 2000. Antigenically and Genetically, these recent H5N1 viruses fall into two groups, one mainly associated with geese, and the other, recently transmitted to ducks. Further, viruses isolated from a goose and a duck in December 2000 have acquired NS, PA, M, and PB2 genes from the aquatic avian influenza gene pool through Reassortment. For pandemic preparedness, it is important to monitor whether these reassortant viruses have the capacity for interspecies transmission to terrestrial poultry or mammals.

  • cocirculation of avian h9n2 and contemporary human h3n2 influenza a viruses in pigs in southeastern china potential for Genetic Reassortment
    Journal of Virology, 2001
    Co-Authors: J S M Peiris, Robert G. Webster, Yi Guan, D Markwell, P Ghose, K F Shortridge
    Abstract:

    Pigs are permissive to both human and avian influenza viruses and have been proposed to be an intermediate host for the genesis of pandemic influenza viruses through Reassortment or adaptation of avian viruses. Prospective virological surveillance carried out between March 1998 and June 2000 in Hong Kong, Special Administrative Region, People's Republic of China, on pigs imported from southeastern China, provides the first evidence of interspecies transmission of avian H9N2 viruses to pigs and documents their cocirculation with contemporary human H3N2 (A/Sydney/5/97-like, Sydney97-like) viruses. All gene segments of the porcine H9N2 viruses were closely related to viruses similar to chicken/Beijing/1/94 (H9N2), duck/Hong Kong/Y280/97 (H9N2), and the descendants of the latter virus lineage. PhyloGenetic analysis suggested that repeated interspecies transmission events had occurred from the avian host to pigs. The Sydney97-like (H3N2) viruses isolated from pigs were related closely to contemporary human H3N2 viruses in all gene segments and had not undergone Genetic Reassortment. Cocirculation of avian H9N2 and human H3N2 viruses in pigs provides an opportunity for Genetic Reassortment leading to the emergence of viruses with pandemic potential.

K F Shortridge - One of the best experts on this subject based on the ideXlab platform.

  • h5n1 influenza viruses isolated from geese in southeastern china evidence for Genetic Reassortment and interspecies transmission to ducks
    Virology, 2002
    Co-Authors: Yi Guan, Malik Peiris, K F Kong, K C Dyrting, T M Ellis, T Sit, L J Zhang, K F Shortridge
    Abstract:

    The H5N1 viruses (H5N1/97) associated with the "bird-flu" incident in the Hong Kong SAR have not been isolated since the slaughter of poultry in December 1997 brought that outbreak to an end. Recent evidence points to this virus as having arisen through a Reassortment of a number of precursor avian viruses and a virus related to Goose/Guangdong/1/96 (H5N1) (Gs/Gd/96) was the likely donor of the H5 hemagglutinin. We characterize the Goose/Guangdong/1/96-like viruses isolated from geese and ducks imported into Hong Kong in the year 2000. Antigenically and Genetically, these recent H5N1 viruses fall into two groups, one mainly associated with geese, and the other, recently transmitted to ducks. Further, viruses isolated from a goose and a duck in December 2000 have acquired NS, PA, M, and PB2 genes from the aquatic avian influenza gene pool through Reassortment. For pandemic preparedness, it is important to monitor whether these reassortant viruses have the capacity for interspecies transmission to terrestrial poultry or mammals.

  • cocirculation of avian h9n2 and contemporary human h3n2 influenza a viruses in pigs in southeastern china potential for Genetic Reassortment
    Journal of Virology, 2001
    Co-Authors: J S M Peiris, Robert G. Webster, Yi Guan, D Markwell, P Ghose, K F Shortridge
    Abstract:

    Pigs are permissive to both human and avian influenza viruses and have been proposed to be an intermediate host for the genesis of pandemic influenza viruses through Reassortment or adaptation of avian viruses. Prospective virological surveillance carried out between March 1998 and June 2000 in Hong Kong, Special Administrative Region, People's Republic of China, on pigs imported from southeastern China, provides the first evidence of interspecies transmission of avian H9N2 viruses to pigs and documents their cocirculation with contemporary human H3N2 (A/Sydney/5/97-like, Sydney97-like) viruses. All gene segments of the porcine H9N2 viruses were closely related to viruses similar to chicken/Beijing/1/94 (H9N2), duck/Hong Kong/Y280/97 (H9N2), and the descendants of the latter virus lineage. PhyloGenetic analysis suggested that repeated interspecies transmission events had occurred from the avian host to pigs. The Sydney97-like (H3N2) viruses isolated from pigs were related closely to contemporary human H3N2 viruses in all gene segments and had not undergone Genetic Reassortment. Cocirculation of avian H9N2 and human H3N2 viruses in pigs provides an opportunity for Genetic Reassortment leading to the emergence of viruses with pandemic potential.

  • evidence for interspecies transmission and Reassortment of influenza a viruses in pigs in southern china
    Virology, 1994
    Co-Authors: Li L Shu, K F Shortridge, Yi P Lin, Stephen M Wright, Robert G. Webster
    Abstract:

    The Asian/57, Hong Kong/68, and Russian/77 pandemics of this century appeared or reappeared in China. Interspecies transmission and Genetic Reassortment of influenza viruses have been implicated in the origin of these human pandemic influenza viruses. Pigs have been suspected to be the "mixing vessel" where Reassortment occurs. To investigate this possibility, 104 porcine influenza viruses collected at random from Southern China from 1976 to 1982, including 32 H3N2 isolates and 72 H1N1 isolates, were studied using dot blot hybridization, partial sequencing, and phyloGenetic analysis. There were 29 of 32 H3N2 isolates characteristic of viruses originally derived from humans; the other 3 isolates were reassortants containing genes from porcine and human influenza viruses. PhyloGenetic analyses of the polymerase B1 (PB1) genes showed that interspecies transmission from humans to pigs has happened multiple times in pigs in Southern China. All 72 H1N1 isolates were of porcine origin characteristic of classical porcine H1N1 influenza virus. Analysis of 624 genes of porcine influenza viruses from Southern China failed to detect any evidence for avian influenza virus genes. This contrasts to what is currently found in Europe, where the majority of porcine influenza virus isolates are of avian origin.

Stuart T. Nichol - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Reassortment among viruses causing hantavirus pulmonary syndrome
    Virology, 1998
    Co-Authors: Luis L Rodriguez, C. J. Peters, Jessica H Owens, Stuart T. Nichol
    Abstract:

    In order to determine the frequency and characteristics of Reassortment among viruses causing hantavirus pulmonary syndrome (HPS), mixed infections were initiated in tissue culture by using two closely related strains of Sin Nombre virus, CC107 (from eastern California) and NMR11 (from New Mexico), which share the same species of rodent host in nature, the deer mouse (Peromyscus maniculatus). Potential reassortant virus plaques were screened by multiplex RT-PCR, using primers specific for individual genome segments of each strain. Reassortant viruses involving the M and S segments and, to a lesser extent, the L segment were detected in 8.5% of 294 progeny plaques tested. In addition, approximately 30% of the progeny virus plaques appeared to contain S or M segments originating from both parental virus strains, i.e., they were diploid. Most of these diploid virus genotypes were not stable, becoming either reassortant or parental virus strains upon plaque-to-plaque virus passage. In contrast to the results above, only one virus reassortant and four diploids were observed among 163 progeny virus plaques from mixed infections between Sin Nombre virus NMR11 and the Genetically more distant Black Creek Canal virus, an HPS-causing virus from Florida, which has the cotton rat (Sigmodon hispidus) as its natural host.

  • naturally occurring sin nombre virus Genetic reassortants
    Virology, 1995
    Co-Authors: Winnie W Henderson, C. J. Peters, Stephen St Jeor, Joan E Rowe, Martha C Monroe, Wesley P Thayer, Stuart T. Nichol
    Abstract:

    Abstract Genetic Reassortment has been shown to play an important role in the evolution of several segmented RNA viruses and in the epidemiology of associated diseases. Sin Nombre (SN) virus is the cause of hantavirus pulmonary syndrome throughout the western United States. Like other hantaviruses, it possesses a genome consisting of three negative-sense RNA segments, S, M, and L. Recent analysis has demonstrated the presence of at least three different hantaviruses in Nevada and eastern California, including SN, Prospect Hill-like, and El Moro Canyon-like viruses. In addition, two distinct lineages of SN virus can be found in Peromyscus maniculatus rodents (sometimes in close proximity) trapped at study sites in this region. Data obtained by phyloGenetic analysis of sequence differences detected among the S, M, and L genome segments of these SN viruses are consistent with Reassortment having taken place between SN virus Genetic variants. The results suggest that M (and to a lesser extent S or L) genome segment flow occurs within SN virus populations in P. maniculatus in this region. No Reassortment was detected between SN virus and other hantavirus types present in the area. This finding suggests that as Genetic distance increases, the frequency of formation of viable reassortants decreases, or that hantaviruses which are primarily maintained in different rodent hosts rarely have the opportunity to Genetically interact.

  • Genetic and serologic analysis of black creek canal virus and its association with human disease and sigmodon hispidus infection
    Virology, 1995
    Co-Authors: Eugene V Ravkov, Thomas G Ksiazek, Pierre E. Rollin, Clarence J Peters, Stuart T. Nichol
    Abstract:

    Abstract Black Creek Canal (BCC) virus is a newly identified virus associated with hantavirus pulmonary syndrome (HPS) in the southeastern United States. Nucleotide sequences were determined for the complete S and M and partial L genomic segments of a BCC virus isolate. PhyloGenetic analysis indicates that each of the virus segments is unique, and there is no evidence of Genetic Reassortment having occurred between this and other previously characterized hantaviruses. All hantavirus-seropositive, wild-caught Sigmodon hispidus which were tested by polymerase chain reaction for the presence of BCC virus RNA were found to be positive, consistent with a chronic virus infection. This finding, together with serologic evidence, confirms S. hispidus as the primary rodent reservoir of this virus. Nucleotide sequence analysis of these PCR products indicates that BCC virus is Genetically diverse and may pose a public health threat throughout much of the extensive range of this rodent species. Immunoprecipitation analysis demonstrated the presence of G1-, G2-, and N-specific antibodies in sera from BCC virus-infected patients with HPS and naturally infected S. hispidus. Comparison of the patterns of protein immunoprecipitation obtained with human acute- and convalescent-phase sera suggests that G1- and G2-specific antibodies increase relative to N-specific antibodies during the course of infection. The ratio of G1 to N protein immunoprecipitation by rodent or human acute-phase sera allowed differentiation of BCC and Sin Nombre virus infections.

  • a newly recognized virus associated with a fatal case of hantavirus pulmonary syndrome in louisiana
    Journal of Virology, 1995
    Co-Authors: Sergey P Morzunov, Christina F Spiropoulou, C. J. Peters, Pierre E. Rollin, Thomas G Ksiazek, V A Semenova, Stuart T. Nichol
    Abstract:

    Genetic analysis of virus detected in autopsy tissues of a fatal hantavirus pulmonary syndrome-like case in Louisiana revealed the presence of a previously unrecognized hantavirus. Nucleotide sequence analysis of PCR fragments of the complete S and M segments of the virus amplified from RNA extracted from the tissues showed the virus to be novel, differing from the closest related hantavirus, Sin Nombre virus, by approximately 30%. Both genome segments were unique, and there was no evidence of Genetic Reassortment with previously characterized hantaviruses. The primary rodent reservoir of Sin Nombre virus, the deer mouse Peromyscus maniculatus, is absent from Louisiana. Thus, the virus detected in Louisiana, referred to here as Bayou virus, must possess a different rodent reservoir.