ETIDIOH - NEW

  ABSTRACT An outbreak of H3N1 low-pathogenic avian influenza virus (LPAIV) in Belgium in 2019 caused unexpected levels of mortality and morbidity in poultry . These viruses possess an NA polymorphism associated with plasminogen (PLG) binding , as well as an atypical sequence around the HA cleavage site ; accordingly, HA cleavage mediated by NA-driven PLG recruitment has been proposed to underlie their systemic spread and pathogenicity. To test this, we established a reverse genetics system for A/chicken/Belgium/460/2019 and created single mutations in HA (K345R) and NA (S122N) that restored the viruses to normal consensus, as well as an HA/NA double mutant. Confirming previous work, trypsin-independent spread and HA cleavage of wild-type Ck/Belgium were observed in the presence of fetal bovine serum containing PLG in vitro. Dose-dependent HA cleavage and trypsin-independent spread were also observed in the presence of purified chicken PLG . Compared to the wild-type virus, both HA...

  Abstract The Caucasus region, including Georgia, is an important intersection for migratory waterbirds , offering potential for avian influenza virus (AIV) transmission between populations from different geographic areas. In 2022 and 2023, wild ducks were sampled during autumn migration events in Georgia to study the genetic relationships and molecular characteristics of influenza strains. Sequencing and phylogenetic analysis were used to compare the sampled strains to reference sequences from Africa, Asia, and Europe , allowing assessment of genetic relationships and virus transmission between migratory birds. Protein language modeling identified potential co-infections. Of 225 duck samples, 128 tested positive for the influenza M gene . 55 influenza-positive samples underwent whole-genome sequencing, revealing significant diversity. Analysis of the hemagglutinin (HA) segment showed notable differences among subtypes. Most samples were H6N1 and H6N6 , but co-infections with comb...

Abstract Avian influenza virus (AIV) is a significant global concern, causing widespread mortality in wild birds, domestic poultry and most recently wild and domestic mammals . This study presents a retrospective analysis of AIV detections in the Republic of Ireland . Data was sourced from official surveillance databases, peer-reviewed literature and grey literature sources. Spatio-temporal, host-specific and subtype patterns were assessed using descriptive statistics, chi-square tests, linear regression and kernel density estimations. A total of 2,888 confirmed AIV detections were recorded from 25 of Ireland's 26 counties . Wild birds accounted for 98.7% of detections, with domestic birds comprising 1.3% and two detections in foxes . H5N1 was the most prevalent subtype (96.7%) followed by H5N8 and H6N1 . Spatial clustering was observed in urban areas, particularly Dublin . The highest seasonal peak occurred during summer, contrasting with traditional winter-associated patterns. Se...

Abstract The interspecies transmission of avian influenza viruses remains a significant public health concern. H6 viruses have gained attention following the first human infection by a chicken-origin H6N1 virus (A/Taiwan/02/2013, Hu/13), highlighting their zoonotic potential . To understand the evolutionary trajectory and mammalian adaptation of this Taiwan lineage , we compared two avian isolates (A/Chicken/Taiwan/CF19/2009, Ck/09; A/Chicken/Taiwan/2267/2012, Ck/12) and Hu/13 in vitro and in vivo. Hu/13 exhibited enhanced replication in MDCK cells , producing larger plaques and higher viral titers than Ck/09 and Ck/12. In BALB/c mice , Hu/13 demonstrated the highest pathogenicity and mortality , followed by Ck/12, while Ck/09 induced minimal morbidity. Hu/13 and Ck/12 replicated efficiently in respiratory tissues , eliciting robust cytokine responses and severe pulmonary lesions . In ferrets , Hu/13 showed relatively efficient transmission , infecting all direct physical-contact and t...