Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 180
Filtrar
4.
Nature ; 437(7062): 1162-6, 2005 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-16208317

RESUMO

Influenza viruses are remarkably adept at surviving in the human population over a long timescale. The human influenza A virus continues to thrive even among populations with widespread access to vaccines, and continues to be a major cause of morbidity and mortality. The virus mutates from year to year, making the existing vaccines ineffective on a regular basis, and requiring that new strains be chosen for a new vaccine. Less-frequent major changes, known as antigenic shift, create new strains against which the human population has little protective immunity, thereby causing worldwide pandemics. The most recent pandemics include the 1918 'Spanish' flu, one of the most deadly outbreaks in recorded history, which killed 30-50 million people worldwide, the 1957 'Asian' flu, and the 1968 'Hong Kong' flu. Motivated by the need for a better understanding of influenza evolution, we have developed flexible protocols that make it possible to apply large-scale sequencing techniques to the highly variable influenza genome. Here we report the results of sequencing 209 complete genomes of the human influenza A virus, encompassing a total of 2,821,103 nucleotides. In addition to increasing markedly the number of publicly available, complete influenza virus genomes, we have discovered several anomalies in these first 209 genomes that demonstrate the dynamic nature of influenza transmission and evolution. This new, large-scale sequencing effort promises to provide a more comprehensive picture of the evolution of influenza viruses and of their pattern of transmission through human and animal populations. All data from this project are being deposited, without delay, in public archives.


Assuntos
Evolução Molecular , Genoma Viral , Vírus da Influenza A/genética , Influenza Humana/virologia , Mutagênese/genética , Animais , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , História do Século XX , História do Século XXI , Humanos , Vírus da Influenza A/classificação , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/fisiologia , Vacinas contra Influenza/história , Vacinas contra Influenza/imunologia , Influenza Humana/epidemiologia , Influenza Humana/transmissão , Influenza Humana/veterinária , Mutação/genética , Neuraminidase/genética , Neuraminidase/metabolismo , New York/epidemiologia , Filogenia , Setor Público , Vírus Reordenados/genética , Análise de Sequência , Fatores de Tempo , Replicação Viral
6.
J Virol ; 79(15): 9926-32, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16014953

RESUMO

In 2003, H5N1 avian influenza virus infections were diagnosed in two Hong Kong residents who had visited the Fujian province in mainland China, affording us the opportunity to characterize one of the viral isolates, A/Hong Kong/213/03 (HK213; H5N1). In contrast to H5N1 viruses isolated from humans during the 1997 outbreak in Hong Kong, HK213 retained several features of aquatic bird viruses, including the lack of a deletion in the neuraminidase stalk and the absence of additional oligosaccharide chains at the globular head of the hemagglutinin molecule. It demonstrated weak pathogenicity in mice and ferrets but caused lethal infection in chickens. The original isolate failed to produce disease in ducks but became more pathogenic after five passages. Taken together, these findings portray the HK213 isolate as an aquatic avian influenza A virus without the molecular changes associated with the replication of H5N1 avian viruses in land-based poultry such as chickens. This case challenges the view that adaptation to land-based poultry is a prerequisite for the replication of aquatic avian influenza A viruses in humans.


Assuntos
Virus da Influenza A Subtipo H5N1 , Vírus da Influenza A/fisiologia , Influenza Humana/veterinária , Doenças das Aves Domésticas/virologia , Adaptação Fisiológica , Animais , Galinhas , China/epidemiologia , Surtos de Doenças , Patos , Furões , Humanos , Vírus da Influenza A/patogenicidade , Influenza Humana/epidemiologia , Influenza Humana/virologia , Camundongos , Dados de Sequência Molecular , Receptores Virais/metabolismo , Inoculações Seriadas/veterinária , Especificidade da Espécie , Virulência , Cultura de Vírus
15.
J Virol ; 79(12): 7535-43, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15919908

RESUMO

It has been shown previously that the nonstructural protein NS1 of influenza virus is an alpha/beta interferon (IFN-alpha/beta) antagonist, both in vitro and in experimental animal model systems. However, evidence of this function in a natural host has not yet been obtained. Here we investigated the role of the NS1 protein in the virulence of a swine influenza virus (SIV) isolate in pigs by using reverse genetics. The virulent wild-type A/Swine/Texas/4199-2/98 (TX/98) virus and various mutants encoding carboxy-truncated NS1 proteins were rescued. Growth properties of TX/98 viruses with mutated NS1, induction of IFN in tissue culture, and virulence-attenuation in pigs were analyzed and compared to those of the recombinant wild-type TX/98 virus. Our results indicate that deletions in the NS1 protein decrease the ability of the TX/98 virus to prevent IFN-alpha/beta synthesis in pig cells. Moreover, all NS1 mutant viruses were attenuated in pigs, and this correlated with the amount of IFN-alpha/beta induced in vitro. These data suggest that the NS1 protein of SIV is a virulence factor. Due to their attenuation, NS1-mutated swine influenza viruses might have a great potential as live attenuated vaccine candidates against SIV infections of pigs.


Assuntos
Vírus da Influenza A/patogenicidade , Influenza Humana/veterinária , Mutação , Doenças dos Suínos/virologia , Proteínas não Estruturais Virais/genética , Animais , Linhagem Celular , Embrião de Galinha , Cães , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/fisiologia , Influenza Humana/imunologia , Influenza Humana/virologia , Interferon-alfa/antagonistas & inibidores , Interferon-alfa/biossíntese , Interferon beta/antagonistas & inibidores , Interferon beta/biossíntese , Suínos , Doenças dos Suínos/imunologia , Virulência , Replicação Viral
19.
Microbiol Immunol ; 48(11): 905-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15557750

RESUMO

Antibodies to influenza A virus were detected using enzyme-linked immunosorbent assay (ELISA) in the sera from two of seven Baikal seals (Phoca sibrica) and from five of six ringed seals (Phoca hispida) in Russia. In a hemagglutination-inhibition test using H1-H15 reference influenza A viruses, ELISA-positive sera from one Baikal seal and four ringed seals reacted to A/Aichi/2/68 (H3N2) and A/Bangkok/1/79 (H3N2) strains. One ringed seal serum sample reacted to A/seal/Massachusetts/1/80 (H7N7). The present results suggested that human-related H3 viruses were prevalent in Baikal seals and ringed seals inhabiting the central Russian Arctic.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Influenza A/classificação , Vírus da Influenza A/imunologia , Influenza Humana/veterinária , Phoca , Animais , Anticorpos Antivirais/imunologia , Feminino , Testes de Inibição da Hemaglutinação , Humanos , Influenza Humana/virologia , Federação Russa
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...