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Showing posts with the label orthomyxovirus

A lethal mouse #model of #Oz virus #infection reveals hepatic involvement and enables evaluation of #antiviral and #vaccine efficacy

  Abstract Oz virus (OZV), a member of the genus Thogotovirus in the family Orthomyxoviridae, is an emerging tick-borne virus reported in Japan . A fatal human case and seroepidemiological evidence of widespread exposure among wild animals and humans suggest its potential public health significance . However, no animal models suitable for pathogenic studies or evaluation of countermeasures are available for OZV. Here, we have established a lethal mouse model of OZV infection using cell-adapted virus and mice lacking type I interferon signaling (B6 Ifnar1 KO mice). OZV infection resulted in 100% mortality and was characterized by robust viral replication in the liver and spleen, severe hepatitis, and acute liver injury . Using this model, we also demonstrated that oral administration of T-705 , an antiviral drug widely used against RNA viruses, as well as immunization with an inactivated whole virus particle vaccine, protected B6 Ifnar1 KO mice from lethal OZV infection by mitigatin...

#Sialic acids are a #barrier to the entry of non-influenza #orthomyxoviruses

  Abstract Sialic acids (SAs) are abundantly expressed on vertebrate cell surfaces and are widely recognized as key viral attachment factors , particularly for influenza viruses . However, their role remains understudied in other orthomyxoviruses, such as thogoto and quaranja viruses , which are tick-borne viruses sporadically infecting humans. Enzymatic removal of SAs increased the infectivity of Thogoto and Dhori viruses , as well as pseudotypes carrying the glycoproteins of Oz, Sinu, and Wellfleet Bay viruses . A similar effect on pseudotype infectivity was observed following the binding of specific lectins to SAs. These findings indicate that, in contrast to influenza viruses, SAs act as a barrier to the entry of these orthomyxoviruses . Experimental evolution of the Sinu and Wellfleet Bay virus glycoproteins revealed point mutations that partially overcame this barrier . Given the abundance of sialic acids in mucosal tissues, we speculate that SAs may contribute to the inabili...

#Genomics of novel #influenza A virus (#H18N12) in #bats, Caribe #Colombia

Abstract Influenza viruses are highly capable of mutating and adapting in mammalian hosts . While these viruses have been extensively studied in birds, research on their presence in bats has been limited. However, influenza viruses circulating in bats have shown notable molecular divergence . The present study aimed to characterize the phylogenetic, evolutionary, and antigenic relationships of an influenza A virus detected in the fishing bat Noctilio albiventris . As part of a pathogen surveillance study of public health interest, 159 rectal samples were collected from bats in the Colombian Caribbean . The samples were sequenced using RNA-Seq. A genome (eight viral contigs) associated with the Orthomyxoviridae family was identified in a pool. Most segments showed approximately 90% similarity with H18N11, except for the neuraminidase. Analysis of the N protein shows that occupies a basal position relative to the N11 subtype, with its divergence date estimated to be approximately 50 year...