In March 2020, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. At the genus rank, 20 new genera were added, two were deleted, one was moved, and three were renamed. At the species rank, 160 species were added, four were deleted, ten were moved and renamed, and 30 species were renamed. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV.

The West Nile virus (WNV), isolated in 1937, is an arbovirus (arthropod-borne virus) that infects thousands of people each year. Despite its burden on global health, little is known about the virus’ biological and evolutionary dynamics. As several lineages are endemic in West Africa, we obtained the complete polyprotein sequence from three isolates from the early 1990s, each representing a different lineage. We then investigated differences in growth behavior and pathogenicity for four distinct West African lineages in arthropod (Ap61) and primate (Vero) cell lines, and in mice. We found that genetic differences, as well as viral-host interactions, could play a role in the biological properties in different WNV isolates in vitro, such as: (i) genome replication, (ii) protein translation, (iii) particle release, and (iv) virulence. Our findings demonstrate the endemic diversity of West African WNV strains and support future investigations into (i) the nature of WNV emergence, (ii) neurological tropism, and (iii) host adaptation.

43 SARS-CoV-2 pulmonary abnormalities in macaques Finch et al. 3 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing an 44 exponentially increasing number of coronavirus disease 19 (COVID-19) cases 45 globally. Prioritization of medical countermeasures for evaluation in randomized 46 clinical trials is critically hindered by the lack of COVID-19 animal models that 47 enable accurate, quantifiable, and reproducible measurement of COVID-19 48 pulmonary disease free from observer bias. We first used serial computed 49 tomography (CT) to demonstrate that bilateral intrabronchial instillation of SARS-50 CoV-2 into crab-eating macaques (Macaca fascicularis) results in mild-to-moderate 51 lung abnormalities qualitatively characteristic of subclinical or mild-to-moderate 52 COVID-19 (e.g., ground-glass opacities with or without reticulation, paving, or 53 alveolar consolidation, peri-bronchial thickening, linear opacities) at typical 54 locations (peripheral>central, posterior and dependent, bilateral, multi-lobar). We 55 then used positron emission tomography (PET) analysis to demonstrate increased 56 FDG uptake in the CT-defined lung abnormalities and regional lymph nodes. 57 PET/CT imaging findings appeared in all macaques as early as 2 days post-58 exposure, variably progressed, and subsequently resolved by 6-12 days post-59 exposure. Finally, we applied operator-independent, semi-automatic quantification 60 of the volume and radiodensity of CT abnormalities as a possible primary endpoint 61 for immediate and objective efficacy testing of candidate medical countermeasures. 62 63

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