https://www.selleckchem.com/products/ABT-888.html H5N8 highly-pathogenic avian influenza viruses (HPAIVs, clade 2.3.4.4) have spread globally via migratory waterfowl. Pekin ducks infected with a UK virus (H5N8-2014) served as the donors of infection in three separate cohousing experiments to attempt onward transmission chains to sequentially introduced groups of contact ducks, chickens and turkeys. Efficient transmission occurred among ducks and turkeys up to the third contact stage, with all (100%) birds becoming infected. Introduction of an additional fourth contact group of ducks to the turkey transmission chain demonstrated retention of H5N8-2014's waterfowl-competent adaptation. However, onward transmission ceased in chickens at the second contact stage where only 13% became infected. Analysis of viral progeny at this contact stage revealed no emergent polymorphisms in the intra-species (duck) transmission chain, but both terrestrial species included changes in the polymerase and accessory genes. Typical HPAIV pathogenesis and mortality occurred in infected chickens and turkeys, contrasting with 5% mortality among ducks. Crown All rights reserved.Protein kinase R plays a key role in innate antiviral immune responses of vertebrate animals. Most mammalian poxviruses encode two PKR antagonists, E3 (dsRNA binding) and K3 (eIF2α homolog) proteins. In this study, the role of K3 family proteins from poxviruses with distinct host tropisms in determining the virus host range was examined in a vaccinia E3L deletion mutant virus. It was found that K3 orthologs from the species-specific poxviruses (taterapox virus, sheeppox virus, myxoma virus, swinepox virus and yaba monkey tumor virus) restored the virus replication competency in cells derived from their natural hosts or related animal species. Further, it was found that the residues located in the helix insert region of the protein, K45 of vaccinia K3 and Y47 of the sheep poxvirus ortholog 011, are critical for the viru