Evolution and ecology of influenza A viruses.

Rg, Webster; Bean, W J; Gorman, Owen T.; Chambers, Thomas M.; Kawaoka, Yoshihiro

doi:10.1128/mmbr.56.1.152-179.1992

Cited by 2,896 publications

(2,186 citation statements)

References 97 publications

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“…The situation recently became more complicated because bats were found to harbour a wide range of mammalian CoVs Poon et al, 2005). It is thus likely that bats serve as reservoirs for CoVs in a similar manner as anseriform birds do for influenza A (Webster et al, 1992). CoVs are responsible for a broad spectrum of diseases, including respiratory and enteric pathologies, both in humans and in animals (Saif, 2004).…”

Section: Introductionmentioning

confidence: 99%

Broadly targeted multiprobe QPCR for detection of coronaviruses: Coronavirus is common among mallard ducks (Anas platyrhynchos)

Muradrasoli

Mohamed

Hornyák

et al. 2009

Journal of Virological Methods

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Coronaviruses (CoVs) can cause trivial or fatal disease in humans and in animals. Detection methods for a wide range of CoVs are needed, to understand viral evolution, host range, transmission and maintenance in reservoirs. A new concept, "Multiprobe QPCR", which uses a balanced mixture of competing discrete non- or moderately degenerated nuclease degradable (TaqMan) probes was employed. It provides a broadly targeted and rational single tube real-time reverse transcription PCR ("NQPCR") for the generic detection and discovery of CoV. Degenerate primers, previously published, and the new probes, were from a conserved stretch of open reading frame 1b, encoding the replicase. This multiprobe design reduced the degree of probe degeneration, which otherwise decreases the sensitivity, and allowed a preliminary classification of the amplified sequence directly from the QPCR trace. The split probe strategy allowed detection of down to 10 viral nucleic acid equivalents of CoV from all known CoV groups. Evaluation was with reference CoV strains, synthetic targets, human respiratory samples and avian fecal samples. Infectious-Bronchitis-Virus (IBV)-related variants were found in 7 of 35 sample pools, from 100 wild mallards (Anas platyrhynchos). Ducks may spread and harbour CoVs. NQPCR can detect a wide range of CoVs, as illustrated for humans and ducks.

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Section: Introductionmentioning

confidence: 99%

Broadly targeted multiprobe QPCR for detection of coronaviruses: Coronavirus is common among mallard ducks (Anas platyrhynchos)

Muradrasoli

Mohamed

Hornyák

et al. 2009

Journal of Virological Methods

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“…In contrast, avian viruses preferentially replicate in epithelial cells of the intestine, are excreted in high concentrations in feces and are transmitted via the fecal-oral route. This is the main mode of transmission for influenza viruses in their natural reservoir, aquatic birds, where these viruses usually do not cause an apparent disease (Hinshaw et al, 1979;van Dijk et al, 2018;Webster et al, 1992Webster et al, , 1978. Influenza viruses occasionally spread from wild waterfowl to humans, other mammals and most frequently to poultry, where they can acquire a higher pathogenicity.…”

Section: Introductionmentioning

confidence: 99%

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Han

Bertzbach

Veit

2019

Veterinary Microbiology

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In contrast to human influenza viruses that replicate in the respiratory tract and are airborne transmitted, avian viruses also replicate in gut epithelial cells and are transmitted via the fecal-oral route. On this route, the virus is exposed to destructive fluids of the digestive tract, which are acidic and contain the proteases pepsin (gizzard) or chymotrypsin and trypsin (intestine). Only the latter enzyme activates virus by cleaving hemagglutinin (HA) into HA 1 and HA 2 subunits.We mimicked the passage of viruses through the gastrointestinal tract by treating them with digestive fluids from chicken and determined titers and integrity of HA by western-blot. Gizzard fluid completely inactivated virions and degrades HA even at a high dilution, but only if the pH was kept acidic. If the fluid is diluted with neutral buffer (mimicking virus uptake with seawater) particles were more resistant. Virions containing an uncleaved HA were even activated suggesting that gastric juice contains a trypsin-like protease. Undiluted intestinal fluid inactivated particles and destroyed HA, but diluted fluid activated virions. A virus isolated from the duck´s intestine is more tolerant against intestinal fluid compared to fowl plague virus suggesting that the former is better adapted to grow in the intestine. We also demonstrate that influenza viruses replicate to high titers in a novel chicken epithelial gut cell line. While viruses with a monobasic HA cleavage site require addition of trypsin, these cells effectively process HA with a polybasic cleavage site, which could be blocked with an inhibitor of the cellular furin protease.

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“…Influenza epidemics and pandemics are constant threats to human health. A large gene pool of influenza A viruses resides in diverse animal reservoirs (Webster et al, 1992), thus influenza viruses with novel genetic composition are able to emerge through genetic reassortment over time, as recently seen with the A(H1N1)pdm09 virus (Smith et al, 2009). The error-prone RNAdependent RNA polymerase (Lauring and Andino, 2010) of the influenza virus further increases the diversity of the influenza genome through random mutation, further increasing the challenge of controlling influenza infections.…”

Section: Introductionmentioning

confidence: 99%

Targeting the host or the virus: Current and novel concepts for antiviral approaches against influenza virus infection

2012

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Influenza epidemics and pandemics are constant threats to human health. The application of antiviral drugs provides an immediate and direct control of influenza virus infection. At present, the major strategy for managing patients with influenza is through targeting conserved viral proteins critical for viral replication. Two classes of conventional antiviral drugs, the M2 ion channel blockers and the neuraminidase inhibitors, are frequently used. In recent years, increasing levels of resistance to both drug classes has become a major public health concern, highlighting the urgent need for the development of alternative treatments. Novel classes of antiviral compounds or biomolecules targeting viral replication mechanism are under development, using approaches including high-throughput small-molecule screening platforms and structure-based designs. In response to influenza virus infection, host cellular mechanisms are triggered to defend against the invaders. At the same time, viruses as obligate intracellular pathogens have evolved to exploit cellular responses in support of their efficient replication, including antagonizing the host type I interferon response as well as activation of specific cellular pathways at different stages of the replication cycle. Numerous studies have highlighted the possibility of targeting virus-host interactions and host cellular mechanisms to develop new treatment regimens. This review aims to give an overview of current and novel concepts targeting the virus and the host for managing influenza.

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Evolution and ecology of influenza A viruses.

Cited by 2,896 publications

References 97 publications

Broadly targeted multiprobe QPCR for detection of coronaviruses: Coronavirus is common among mallard ducks (Anas platyrhynchos)

Broadly targeted multiprobe QPCR for detection of coronaviruses: Coronavirus is common among mallard ducks (Anas platyrhynchos)

Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens

Targeting the host or the virus: Current and novel concepts for antiviral approaches against influenza virus infection

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