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Showing posts from January 24, 2025

Novel introductions of #human-origin #H3N2 #influenza viruses in #swine, #Chile

Abstract Influenza A virus (IAV) continuously threatens animal and public health globally , with swine serving as a crucial reservoir for viral reassortment and evolution . In Chile , H1N2 and H3N2 subtypes were introduced in the swine population before the H1N1 2009 pandemic, and the H1N1 was introduced from the H1N1pdm09 by successive reverse zoonotic events . Here, we report two novel introductions of IAV H3N2 human-origin in Chilean swine during 2023. Our study reveals a closer relationship between recent human seasonal H3N2 and novel swine strains. Interestingly, one strain maintains all the genes from the original human virus , but the other strain is already a reassortment of human H3N2 and an H1N2 previously observed on the farm. Observing global IAV sequences, a similar pattern was identified in the USA confirming the reverse zoonotic potential of current seasonal human H3N2 strains. These results highlight the importance of ongoing surveillance and reinforcing biosecurity in ...

Phylogeography and biological characterization of #H12N2 virus isolated from whooper #swan in Central #China

Abstract Wild birds and waterfowl serve as the natural reservoirs of avian influenza viruses (AIVs). When AIVs originating from wild birds cross species barriers to infect mammals or humans , they pose a significant threat to public health . The H12 subtype of AIVs primarily circulates in wild birds, with relatively few isolates reported worldwide , and the evolutionary and biological characteristics of H12 subtype AIVs remain largely unknown. In this study, we analyzed the spatiotemporal distribution of H12 subtype AIVs worldwide and conducted a comprehensive investigation into the evolutionary and biological characteristics of an H12N2 virus isolated from a whooper swan in Central China . Phylogenetic analysis revealed that the H12N2 isolate belongs to the Eurasian lineage , with its HA gene likely originating from a duck-derived H12N5 virus and its NA gene potentially derived from an H9N2 virus , indicating that it is a complex reassorted virus. Animal experiments in domestic ducks ...

#USA, Monitoring for Avian #Influenza A(#H5) Virus In #Wastewater (Jan 12-18 '25)

 {Excerpt} Time Period: January 12 - January 18, 2025 -- H5 Detection : 35 sites ( 10.4% ) -- No Detection : 301 sites ( 89.6% ) -- No samples in last week : 62 sites (...) Source: US Centers for Disease Control and Prevention,  https://www.cdc.gov/bird-flu/h5-monitoring/index.html _____

#Antiviral activity of #tecovirimat against #monkeypox virus clades 1a, 1b, 2a, and 2b

{Excerpt} The zoonotic Orthopoxvirus monkeypox virus includes two main clades (ie, 1 and 2) relevant to human transmission .1 Two major outbreaks of monkeypox virus have occurred since 2022,1–3 and were declared public health emergencies of international concern by WHO in July, 2022, and August, 2024. The first outbreak was caused by a clade 2b strain that quickly spread worldwide, resulting in approximately 100 000 cases and 200 deaths.3 In the second outbreak, the novel clade 1b emerged .4 As of December, 2024, this upsurge has resulted in more than 55 000 reported or suspected cases and approximately 1000 deaths in DR Congo and neighbouring countries, including Burundi, Rwanda, Uganda , and Angola .4 A few imported clade 1b cases have also been reported in the UK, Sweden, Germany, Belgium, France, the USA, Canada , and Thailand .5 Prevention measures include patient isolation and care as well as vaccines. (...) Source: Lancet Infectious Diseases,  https://www.thelancet.com/journ...

Characterization of novel highly pathogenic avian #influenza A(#H5N6) clade 2.3.4.4b virus in wild #birds, East #China, 2024

{Excerpt} Dear Editor, The highly pathogenic avian influenza viruses (HPAIVs) are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and public health . Wild birds have been recognized as the primary reservoirs for influenza A virus, and some species show little sign of clinical disease or even can be asymptomatic during long distance carriers of the virus (Lycett et al., 2019). Since it was first discovered in 1959, the H5Nx HPAIVs have spread globally and cause outbreaks in wild birds, poultry and sporadic human and other mammalian infections (Lycett et al., 2019). Due to the reassortant events of diverse strains facilitated by migratory waterfowl, the clade 2.3.4.4 of H5Nx viruses acquiring neuraminidase (NA) gene from other low pathogenicity avian influenza viruses (LPAIVs) emerged in 2014 and gradually became the dominant sub-clade (Lee et al., 2017). The genetic diversity of clade 2.3.4.4...

#Receptor #binding, #structure, and #tissue #tropism of #cattle-infecting #H5N1 avian #influenza virus #hemagglutinin

Summary The ongoing circulation of highly pathogenic avian influenza (HPAI) A (H5N1) viruses , particularly clade 2.3.4.4b strains , poses a significant threat to animal and public health . Recent outbreaks in cattle highlight concerns about cross-species transmission and zoonotic spillover . Here, we found that the hemagglutinin (HA) protein from a cattle-infecting H5N1 virus has acquired slight binding to human-like α2-6-linked receptors while still exhibiting a strong preference for avian-like α2-3-linked sialic acid receptors. Immunohistochemical staining revealed HA binding to bovine pulmonary and mammary tissues , aligning with clinical observations. HA also binds effectively to human conjunctival, tracheal, and mammary tissues , indicating a risk for human transmission , notably in cases of conjunctivitis . High-resolution cryo-electron microscopy (cryo-EM) structures of this H5 HA in complex with either α2-3 or α2-6 receptors elucidate the molecular mechanisms underlying its re...