Publications by authors named "Mathilde Richard"

Extracellular vesicles (EVs) are cell-derived small membrane structures that transport various molecules. They have emerged as potential circulating biomarkers for monitoring responses to cancer therapies. This study aimed to comprehensively characterize plasma-carried EVs in hormone receptor-positive (HR) metastatic breast cancer (MBC) patients treated with first-line CDK4/6 inhibitors (iCDK4/6) combined with endocrine therapy.

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Article Synopsis
  • An increase in spillover events of avian influenza A(H5N1) to mammals indicates that certain virus strains are adapting for better transmission among mammals.
  • Research using air-sampling devices to monitor ferrets shows that earlier strains of A(H5N1) didn't effectively transmit due to low airborne virus shedding, not a lack of mutations needed for adaptation.
  • In contrast, while human A(H1N1) was easily detected in the air, some A(H5N1) strains from 2005 and 2024 were not, although a couple of ferrets infected with a 2022 European polecat strain and a 2024 strain from a farm worker did shed infectious virus.
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Highly pathogenic avian influenza A(H5) viruses globally impact wild and domestic birds, and mammals, including humans, underscoring their pandemic potential. The antigenic evolution of the A(H5) hemagglutinin (HA) poses challenges for pandemic preparedness and vaccine design. Here, the global antigenic evolution of the A(H5) HA was captured in a high-resolution antigenic map.

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Highly pathogenic avian influenza viruses (HPAIVs) cause severe hemorrhagic disease in terrestrial poultry and are a threat to the poultry industry, wild life, and human health. HPAIVs arise from low pathogenic avian influenza viruses (LPAIVs), which circulate in wild aquatic birds. HPAIV emergence is thought to occur in poultry and not wild aquatic birds, but the reason for this species-restriction is not known.

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Highly pathogenic avian influenza viruses (HPAIVs) cause severe disease and high fatality in poultry. They emerge exclusively from H5 and H7 low pathogenic avian influenza viruses (LPAIVs). Although insertion of a furin-cleavable multibasic cleavage site (MBCS) in the hemagglutinin gene was identified decades ago as the genetic basis for LPAIV-to-HPAIV transition, the exact mechanisms underlying said insertion have remained unknown.

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Influenza A viruses of the H2N2 subtype sparked a pandemic in 1957 and circulated in humans until 1968. Because A/H2N2 viruses still circulate in wild birds worldwide and human population immunity is low, the transmissibility of six avian A/H2N2 viruses was investigated in the ferret model. None of the avian A/H2N2 viruses was transmitted between ferrets, suggesting that their pandemic risk may be low.

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  • * Vaccination programs in poultry might help control these viruses, but they also create immune pressure that can accelerate antigenic evolution, making it harder to prepare for pandemics.
  • * The study analyzed the global antigenic diversity of A/H7 viruses from 2013 to 2019, identifying key genetic changes that affect their evolution, which can improve surveillance, vaccine design, and overall pandemic preparedness.
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Continued circulation of A/H5N1 influenza viruses of the A/goose/Guangdong/1/96 lineage in poultry has resulted in the diversification in multiple genetic and antigenic clades. Since 2009, clade 2.3.

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Highly pathogenic avian influenza viruses (HPAIVs) typically emerge from low-pathogenic avian influenza viruses (LPAIVs) of the H5 and H7 subtypes upon spillover from wild aquatic birds into poultry. The conversion from LPAIV to HPAIV is characterized by the acquisition of a multibasic cleavage site (MBCS) at the proteolytic cleavage site in the viral binding and fusion protein, hemagglutinin (HA), resulting in cleavage and activation of HA by ubiquitously expressed furin-like proteases. The ensuing HPAIVs disseminate systemically in gallinaceous poultry, are endotheliotropic, and cause hemorrhagic disease with high mortality.

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  • * Research into the evolution of HPAI H5N1 has largely focused on respiratory infections, but this study aims to explore the evolutionary dynamics of the virus when it infects the CNS, revealing variability in replication among individual ferrets.
  • * The study identified specific genetic mutations in the virus that enhance its polymerase activity in the lab, yet these mutations also appeared to limit the virus's ability to spread to other body parts while showing potential adaptability within the CNS. *
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Highly pathogenic avian influenza viruses (HPAIVs) of the Goose/Guangdong (Gs/Gd) lineage are an emerging threat to wild birds. In the 2016-2017 H5N8 outbreak, unexplained variability was observed in susceptible species, with some reports of infected birds dying in high numbers and other reports of apparently subclinical infections. This experimental study was devised to test the hypothesis that previous infection with a less-virulent HPAIV (i.

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Article Synopsis
  • * The key factor for the virulence of HPAIVs is a feature called the multi-basic cleavage site (MBCS) in the hemagglutinin (HA) protein, allowing the virus to be activated by common enzymes, which leads to widespread infection in birds.
  • * The article reviews recent studies on how low pathogenic viruses convert to highly pathogenic forms, focusing on HA cleavage efficiency and the mechanisms that facilitate the acquisition of MBCS, as well as theories about why H5 and H7 viral sequences are
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A vast diversity of 16 influenza hemagglutinin (HA) subtypes are found in birds. Interestingly, viruses from only two subtypes, H5 and H7, have so far evolved into highly pathogenic avian influenza viruses (HPAIVs) following insertions or substitutions at the HA cleavage site by the viral polymerase. The mechanisms underlying this striking subtype specificity are still unknown.

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Seasonal influenza vaccination takes into account primarily hemagglutinin (HA)-specific neutralizing antibody responses. However, the accumulation of substitutions in the antigenic regions of HA (i.e.

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Highly pathogenic avian influenza viruses (HPAIVs) cause fatal systemic infections in chickens, which are associated with endotheliotropism. HPAIV infections in wild birds are generally milder and not endotheliotropic. Here, we aimed to elucidate the species-specific endotheliotropism of HPAIVs using primary chicken and duck aortic endothelial cells (chAEC and dAEC respectively).

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Avian influenza viruses from the A/H5 A/goose/Guangdong/1/1996 (GsGd) lineage pose a continuing threat to animal and human health. Since their emergence in 1997, these viruses have spread across multiple continents and have become enzootic in poultry. Additionally, over 800 cases of human infection with A/H5 GsGd viruses have been reported to date, which raises concerns about the potential for a new influenza virus pandemic.

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SARS-CoV-2 emerged in late 2019 and caused a pandemic, whereas the closely related SARS-CoV was contained rapidly in 2003. Here, an experimental set-up is used to study transmission of SARS-CoV and SARS-CoV-2 through the air between ferrets over more than a meter distance. Both viruses cause a robust productive respiratory tract infection resulting in transmission of SARS-CoV-2 to two of four indirect recipient ferrets and SARS-CoV to all four.

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The presence of multiple basic amino acids in the protease cleavage site of the hemagglutinin (HA) protein is the main molecular determinant of virulence of highly pathogenic avian influenza (HPAI) viruses. Recombination of HA RNA with other RNA molecules of host or virus origin is a dominant mechanism of multibasic cleavage site (MBCS) acquisition for H7 subtype HA. Using alignments of HA RNA sequences from documented cases of MBCS insertion due to recombination, we show that such recombination with host RNAs is most likely to occur at particular hotspots in ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), and viral RNAs.

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Article Synopsis
  • - In 2014, the A/H10N7 influenza virus outbreak among seals in Northern Europe led to significant declines in seal populations, highlighting the virus's impact on wildlife.
  • - The study focused on changes in the hemagglutinin surface protein of the seal A/H10N7 virus, which enhanced its stability and ability to bind to receptors, particularly those similar to human receptors.
  • - Findings suggest that the seal variant of the virus can transmit via aerosol or respiratory droplets in ferrets, indicating the potential risk this avian-origin influenza virus poses to other mammals, including humans.
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SARS-CoV-2, a coronavirus that emerged in late 2019, has spread rapidly worldwide, and information about the modes of transmission of SARS-CoV-2 among humans is critical to apply appropriate infection control measures and to slow its spread. Here we show that SARS-CoV-2 is transmitted efficiently via direct contact and via the air (via respiratory droplets and/or aerosols) between ferrets, 1 to 3 days and 3 to 7 days after exposure respectively. The pattern of virus shedding in the direct contact and indirect recipient ferrets is similar to that of the inoculated ferrets and infectious virus is isolated from all positive animals, showing that ferrets are productively infected via either route.

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  • * A study analyzed the genetic and antigenic characteristics of 35 H5N1 viruses from humans, finding few markers for human adaptation and a low incidence of the PB2-E627K substitution linked to severe virulence in other strains.
  • * The research identified two distinct antigenic clusters among the viruses, emphasizing the need for ongoing monitoring of H5N1 virus evolution to assess potential risks to human health in Indonesia.
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The continual emergence of novel influenza A strains from non-human hosts requires constant vigilance and the need for ongoing research to identify strains that may pose a human public health risk. Since 1999, canine H3 influenza A viruses (CIVs) have caused many thousands or millions of respiratory infections in dogs in the United States. While no human infections with CIVs have been reported to date, these viruses could pose a zoonotic risk.

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Human influenza A viruses are known to be transmitted via the air from person to person. It is unknown from which anatomical site of the respiratory tract influenza A virus transmission occurs. Here, pairs of genetically tagged and untagged influenza A/H1N1, A/H3N2 and A/H5N1 viruses that are transmissible via the air are used to co-infect donor ferrets via the intranasal and intratracheal routes to cause an upper and lower respiratory tract infection, respectively.

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The acquisition of a multibasic cleavage site (MBCS) in the hemagglutinin (HA) glycoprotein is the main determinant of the conversion of low pathogenic avian influenza viruses into highly pathogenic strains, facilitating HA cleavage and virus replication in a broader range of host cells. In nature, substitutions or insertions in HA RNA genomic segments that code for multiple basic amino acids have been observed only in the HA genes of two out of sixteen subtypes circulating in birds, H5 and H7. Given the compatibility of MBCS motifs with HA proteins of numerous subtypes, this selectivity was hypothesized to be determined by the existence of specific motifs in HA RNA, in particular structured domains.

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