Cience and Technology Study Project (172102110099) and National College Student’s Innovation and Entrepreneurship Training Plan (201710471022). We thank Mrs. Kai Tan for assisting within the preparation of this manuscript.DeclarationsConflict of interest The authors declare that they have no conflict of interest.
Because December 2019, a novel coronavirus illness 2019 (COVID-19) has swiftly spread all over the globe to lead to a pandemic (Li et al., 2020b; Zhu et al., 2020). The pneumonia causative agent was identified to become a new coronavirus, extreme acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As of April six, 2021, extra than 130 million instances have been confirmed globally, including approximately 2.85 million deaths. The nonetheless ongoing pandemic represents one of the most recent instance of how emerging or re-emerging human or zoonotic viruses pose a threat to public overall health. These viruses include things like but not restricted to Ebola virus (EBOV), Zika virus (ZIKV), West Nile virus (WNV), yellow fever virus (YFV), dengue virus (DENV), henipaviruses (Nipah, Hendra), SARS-CoV, Middle East respiratory syndrome (MERS-CoV), Lassa virus (LASV), Crimean-Congo hemorrhagic fever virus (CCHFV), Rift Valley fever virus (RVFV), chikungunya virus (CHIKV), human immunodeficiency virus (HIV) and influenza A virus (IAV). We listed six viral families in which numerous viruses have merged or remerged in current years to possess triggered or potentially cause an epidemic or pandemic, including Coronaviridae, Filoviridae, Flaviviridae, Arenaviridae, Nairoviridae, and Orthomyxoviridae. The genome structure, critical viruses, and essential attributes relating to virus-host interactions are summarized in Table 1. The emerging or remerging virus outbreak has emphasized the urgent have to have for preventative or remedy regimens. Vaccines are recognized as a preferred promising line of defense. On the other hand, nNOS supplier vaccine development is actually a complex method and a number of challenges are involved in light from the factFrontiers in Pharmacology | www.frontiersin.orgMay 2021 | Volume 12 | ArticleLi and PengDrug Repurposing for Antiviral DiscoveryTABLE 1 | Important emerging or remerging viruses. Virus family members Coronaviridae Genome ss (+) RNA; 262 kb Vital viruses SARS-CoV, SARS-CoV-2, MERS-CoV, HCoV-229 E, HCoV-OC43, HCoV-NL63, HCoV-HKU1 Key features/Virus-host interactions Enveloped viruses; case PKCη review fatality rate: 30 (MERS-CoV), 10 (SARS-CoV), 3 (SARS-CoV-2); receptor: ACE2 (SARS-CoV, SARS-CoV-2); DPP4 (MERS-CoV); S protein proteolytic cleavage by cathepsins or TMPRSS2 is needed for infection; RNA proofreading is viable as a result of the exoribonuclease activity Enveloped viruses; bring about hemorrhagic fever, liver damage, congenital malformations (microcephaly); transmission by vectors like mosquitos or ticks Enveloped filamentous virions can exceed to 14,000 nm in length; bring about fatal viral hemorrhagic fevers; case fatality price: from 25 to 90 ; DC-SIGN, or integrins as attachment aspect; receptor: NPC1 (EBOV) Enveloped viruses; case fatality rate: 200 (JUNV), 1 (LASV); entry components: Alpha-dystroglycan, LAMP1 (LASV); trigger hemorrhagic fever; virus spreads via rodents Enveloped viruses with circular genome; case fatality price: one hundred (CCHFV); virus entry is clathrin-, pHand cholesterol dependent; trigger hemorrhagic fever; transmission by vectors like ticks Enveloped viruses; genome reassortment is widespread; case fatality rate varies, 2 (1918 H1N1) Ref de Wit et al. (2016); Chen (2020)Flaviviridaess (+) RNA; 9.62.three kb.