ETIDIOH - NEW

  ABSTRACT Amoeboflagellates of the genus Naegleria are free-living protists ubiquitously found in soil and freshwater habitats worldwide. They include the “brain-eating amoeba” Naegleria fowleri , an opportunistic pathogen that causes primary amoebic meningoencephalitis , a rare but fatal infection of humans. Beyond their direct pathogenicity, protists can also act as environmental reservoirs for intracellular bacterial pathogens , such as Legionella spp., to persist and multiply in the environment. In this study, we carried out single-cell genome sequencing of two uncultivated Naegleria species isolated from the River Leam in England . From single cells, we generated two highly complete Naegleria genomes . Phylogenetic analyses placed these species as close relatives of Naegleria fultoni and Naegleria pagei . Exploring Naegleria evolutionary genomics, we identified gene families encoding antistasin-like domains, which have been characterized as factors that inhibit coagulation in...

  ABSTRACT Alterations in the PB2-627 domain of avian influenza virus (AIV) can potentially increase the risk of cross-host species infections in humans and mammals . Recently, there has been a rise in human cases of AIV infections without the presence of the known mammalian determinant PB2-E627K . Here, we identified a variant, PB2-627V , which has evolved in poultry and has contributed to the increase in human AIV infections . By screening global PB2 sequences , we discovered a new independent cluster of PB2-627V that emerged in the 2010s , prevalent in avian, mammalian, and human AIV isolates , including those of H9N2, H7N9, H3N8, 2.3.4.4b H5N1 , and other subtypes. We functionally assessed its host adaptation , fitness , and transmissibility across three subtypes of AIVs (H9N2, H7N9, and H3N8) in different host models . PB2-627V combines the viral properties of avian-like PB2-627E and human-like PB2-627K , facilitating AIVs to efficiently infect and replicate in chickens and mi...

  Abstract In recent years, the four main swine influenza A virus (IAV-S) subtypes circulating in swine in the EU have been H1avN1, H1huN2, H1N1pdm09, and H3N2 . The latter emerged in 1984 from a reassortment event between a human seasonal H3N2 and H1avN1, and is currently detected at low prevalence in swine in Italy . Here, we describe nine H3N2 IAV-S isolates belonging to three novel genotypes , first detected in Italy in 2021 , likely resulting from reassortment events between swine and human IAVs. The first genotype was characterized by a hemagglutinin (H3 HA) of human seasonal origin , a neuraminidase (N2 NA) derived from H1huN2 strains circulating in Italian swine, and an avian-like internal gene cassette (IGC). The second genotype differed in its IGC constellation: PB2, PB1, PA and NP segments were of pandemic origin ( pdm09 ), while NS and M segments derived from the Eurasian avian-like lineage . The third genotype combined a human-derived H3, a Gent/84-derived N2, and a pd...

  Abstract Influenza A virus (IAV) infection is associated with a wide variety of neurological complications , of which mild complications like impaired cognitive functioning are most prominent . Even though several studies have shown that many influenza viruses can enter the CNS, the neuropathogenesis of seasonal ( H3N2 and H1N1 ) and pandemic (pH1N1 2009) IAV infections is poorly understood. Therefore, we aimed to investigate the cellular tropism, replication efficiency and associated functional consequences using a human stem cell-derived neural co-culture model of neurons and astrocytes . All viruses were able to infect neurons in the co-culture model, although this infection did not result in efficient replication and release of progeny virus. In addition, infection did not result in visible cell death or apoptosis. However, functional analyses revealed that IAV inoculation resulted in a reduction of spontaneous neural activity and a partial reduction of neural excitability. T...