Grand Challenge in Human/Animal Virology: Unseen, Smallest Replicative Entities Shape the Whole Globe

摘要

By far the most abundant species in nature is the virus that cannot replicate by itself. Viruses, parasitic entities, are found in virtually all unicellular and multicellular creatures. Viruses are everywhere. While smallest in size among all species, they can ingeniously replicate, persist, and survive in their individual hosts and/or host populations, and are transmittable among hosts. Viruses are sometimes inflicting or fatal for host species and are sometimes inter-species replicons. They keep interacting with their hosts in numerous different manners. Unseen viruses thus can reshuffle the whole world through accumulations of their subtle biological effects. In other words, viruses can shape the entire environment around us and are able to directly and/or indirectly influence us by their biologic activities. Virology is a multidisciplinary research field and, as an academic discipline of the biology, it extensively analyzes all aspects of viruses derived from every living species by scientific systems/methodologies currently available to us as exemplified and fully described in a series of Frontiers special issues designated “Research Topic” (RT) in the Virology section of Frontiers in Microbiology (Nomaguchi and Adachi, 2010 , 2017 ; Miyazaki et al., 2012 ; Nomaguchi et al., 2012 ; Berkhout and Coombs, 2013 ; Sato et al., 2013 ; Adachi and Miura, 2014 ; Dutilh et al., 2017 ; Sanfa?on, 2017 ; Yamamoto et al., 2017 ). I wish to emphasize here again that virology is a branch of biological sciences studying the fundamental attributes of a wide variety of unique characteristic viruses. Virology concerns biological issues in a broad sense. In the past decade, as many as of 1,500 articles approximately have been published and almost 80 RTs for specific subjects have been issued or are on the way in the Virology section. During this period, we have seen constant and vast increases both in virology-specific, in a narrow sense, articles, and in those giving more conceptual and general knowledge of the biology. Notably, the observed advances frequently have been accompanied by remarkable development of novel innovative technologies. In the next decade, concomitant with successful proceeding of the powerful and sharp analyzing systems and/or methods such as computational biology, structural biology, bioinformatics, multi-omics, next-generation sequencing, genome editing, single-cell methodology, and organoid technology (Bai et al., 2015 ; Angermueller et al., 2016 ; Chen et al., 2017 ; Dutta et al., 2017 ; Hasin et al., 2017 ; Adli, 2018 ; Artegiani and Clevers, 2018 ; Cheng, 2018 ; Ibrahim et al., 2018 ; Rossi et al., 2018 ; Sbalzarini and Greber, 2018 ; van Dijk et al., 2018 ; Pickar-Oliver and Gersbach, 2019 ), virology will certainly continue to contribute much to the progress in all areas of the basic biology from molecular and structural biology to environmental science. In addition, virology will surely represent one of major driving forces to solve a wide variety of practical issues, which are directly or indirectly related to the virus issue itself, i.e., nanotechnology, viral vectors, antiviral drugs, vaccines, gene therapy, interferon therapy, immune therapy, and so on (De Clercq, 2007 ; Guimar?es et al., 2015 ; Szunerits et al., 2015 ; De Clercq and Li, 2016 ; Athanasopoulos et al., 2017 ; Grimm and Büning, 2017 ; Singh et al., 2017 ; Snell et al., 2017 ; Chambers et al., 2018 ; Colino et al., 2018 ; Kaufmann et al., 2018 ; Ono et al., 2018 ; Sulczewski et al., 2018 ; Vetter et al., 2018 ; Dionne, 2019 ; Graham et al., 2019 ). It is well-expected from our plentiful experience in the past decade that the Virology section, as an outstanding communication platform, plays a critical and central role in various activities of basic and applied sciences. Human and animal virology investigates viruses that infect human and all species of animals. Upon replication, some viruses are damaging for their hosts to various degrees whereas others rather peacefully co-exist with the hosts. Among these viruses, those that cause serious infectious diseases in human and/or animals, are medically, socially, and economically of particular importance, as a matter of course for scientific significance. In fact, our Virology section has published numerous articles related to this kind of human and animal viruses and has edited relevant RTs in the past decade. On one hand, more general subjects covering various pathogenic viruses and related research areas have been targeted as well. Of socially important pathogenic viruses, some are solely tropic for humans, HIV-1 as an example (Hatziioannou et al., 2006 , 2009 ; Kamada et al., 2006 ; Nomaguchi et al., 2008 , 2013b ), and some like human norovirus are known not to replicate in cultured cells (Duizer et al., 2004 ; Herbst-Kralovetz et al., 2013 ; Ettayebi et al., 2016 ; Murakami et al., 2020 ). Indeed, these viral properties hamper and limit our experimental strategies, and ar