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Several Avian paramyxoviruses 1 (synonymous with Newcastle disease virus or NDV, used hereafter) classification systems have been proposed for strain identification and differentiation. These systems pioneered classification efforts; however, they were based on different approaches and lacked objective criteria for the differentiation of isolates. These differences have created discrepancies among systems, rendering discussions and comparisons across studies difficult. Although a system that used objective classification criteria was proposed by Diel and co-workers in 2012, the ample worldwide circulation and constant evolution of NDV, and utilization of only some of the criteria, led to identical naming and/or incorrect assigning of new sub/genotypes. To address these issues, an international consortium of experts was convened to undertake in-depth analyses of NDV genetic diversity. This consortium generated curated, up-to-date, complete fusion gene class I and class II datasets of all known NDV for public use, performed comprehensive phylogenetic neighbor-Joining, maximum-likelihood, Bayesian and nucleotide distance analyses, and compared these inference methods. An updated NDV classification and nomenclature system that incorporates phylogenetic topology, genetic distances, branch support, and epidemiological independence was developed. This new consensus system maintains two NDV classes and existing genotypes, identifies three new class II genotypes, and reduces the number of sub-genotypes. In order to track the ancestry of viruses, a dichotomous naming system for designating sub-genotypes was introduced. In addition, a pilot dataset and sub-trees rooting guidelines for rapid preliminary genotype identification of new isolates are provided. Guidelines for sequence dataset curation and phylogenetic inference, and a detailed comparison between the updated and previous systems are included. To increase the speed of phylogenetic inference and ensure consistency between laboratories, detailed guidelines for the use of a supercomputer are also provided. The proposed unified classification system will facilitate future studies of NDV evolution and epidemiology, and comparison of results obtained across the world.

These AIV subtypes could spark a human pandemic once adapted through mutation. Why have they persisted in China? How have they been circulating in China? What strategies have been implemented in China to control the spread of AIV? How scientific and effective are these strategies? What lessons can we learn from the experience in China for the control of AIV? We attempted to answer these questions in this review based on relevant studies in the literature and our unpublished surveillance data collected over a 12-year period from 2007 to 2018 (Tables 1 and 2), with the aim to provide insights to improve guidelines for the control of AIV, both in China and globally. 2 | ROOTS OF THE PROB LEMS The prevalence of AIV in China is rooted in its ingrained ecosystem and socioeconomic features. First, billions of wild birds come into contact with domestic birds, either directly or indirectly,

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BackgroundSimultaneous and sequential allantoic cavity inoculations of Specific-pathogen-free (SPF) chicken eggs with Influenza virus (AIV) and Newcastle disease virus (NDV) demonstrated that the interaction of AIV and NDV during co-infection was variable. Our research revisited the replication interference potential of AIV and NDV using real-time reverse transcription–polymerase chain reaction (real-time RT-PCR) for AIV and NDV to specifically detect the viral genomes in mixed infections.ResultsData from this survey showed that when different doses of NDV (Lasota or F48E8) and AIV (F98 or H5N1) were simultaneously inoculated into embryonating chicken eggs (ECE), interference with the growth of NDV occurred, while interference with the growth of AIV did not occur. When equal amount of the two viruses were sequentially employed, the degree of interference was dependent upon the time of superinfection and the virulence of virus.ConclusionAIV have a negative impact on NDV growth if they are inoculated simultaneously or sequentially and that the degree of interference depended upon the quantity and relative virulence of the virus strains used; however, interference with AIV was not observed. Only if NDV were inoculated at an earlier time will NDV able to interfere with the growth of AIV.