Virus-induced pathogenesis, vaccine development, and diagnosis of novel H7N9 avian influenza A virus in humans: a systemic literature review

Abstract

H7N9 avian influenza virus (AIV) caused human infections in 2013 in China. Phylogenetic analyses indicate that H7N9 AIV is a novel reassortant strain with pandemic potential. We conducted a systemic review regarding virus-induced pathogenesis, vaccine development, and diagnosis of H7N9 AIV infection in humans. We followed PRISMA guidelines and searched PubMed, Web of Science, and Google Scholar to identify relevant articles published between January 2013 and December 2018. Pathogenesis data indicated that H7N9 AIV belongs to low pathogenic avian influenza, which is mostly asymptomatic in avian species; however, H7N9 induces high mortality in humans. Sporadic human infections have recently been reported, caused by highly pathogenic avian influenza viruses detected in poultry. H7N9 AIVs resistant to adamantine and oseltamivir cause severe human infection by rapidly inducing progressive acute community-acquired pneumonia, multiorgan dysfunction, and cytokine dysregulation; however, mechanisms via which the virus induces severe

Spatiotemporal Associations and Molecular Evolution of Highly Pathogenic Avian Influenza A H7N9 Virus in China from 2017 to 2021

“…As a result, at least some aspects of virus evolution and emergence are repeatable and predictable [24]. Additionally, since the HA protein is the primary target of neutralizing antibodies [50] and determines specificity for efficient virus transmission between individuals and between species [51], parallel/convergent evolution on HA could not only alter the receptor binding affinity but also affect antigenicity. In this study, we found several parallel/convergent mutations on HA1, including four in the RBS (125 in 130-loop, 151 in 150-loop, 177 in 190-helix, and 217 in 220-loop).…”

The Silent Partners

“…There have been 5 documented H7N9 outbreaks in China from 2013 to 2017, but human-tohuman transmission was only evident to some extent in the last outbreak (32)(33)(34), consistent with a Vx that is not yet humanized and likely to cause far fewer cases than other respiratory pathogens. However, considering the estimated CFR for H7N9 patients is ~30% (30,34), even if only 10% of the COVID-19 patients in Wuhan also had H7N9 it would explain the high CFR initially reported in China.…”

“…Of note, H7N9 infections in humans are described as indistinguishable from the 2003 definition of SARS (27)(28)(29), causing fever, hypenia, long-term damage to lung and cardiac tissue in recovered patients, and high mortality rate. Moreover, H7N9 viruses can be antigenically and genetically very different from common fluA strains (e.g H1N1), making them undetectable by standard flu tests and likely to go undiagnosed in hospital settings (30)(31).…”

The Silent Partners

“…There have been 5 documented H7N9 outbreaks in China from 2013 to 2017, but human-tohuman transmission was only evident to some extent in the last outbreak (32)(33)(34), consistent with a Vx-like pathogen that is not yet humanized and likely to cause far fewer cases than other respiratory pathogens. However, considering the estimated CFR for H7N9 patients is ~30% (30,34), even a small proportion of COVID-19 patients that also have Vx (or specifically H7N9), could explain the high CFR reported in some regions/periods, i.e Wuhan in February, Lombardi in March/April, and later in NYC.…”