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Abstract Book

EMERGING AND EVOLVING – viral discovery, emergence and evolution Abstract final identifier: 84 MEGATAXONOMY OF NEGATIVE-SENSE RNA VIRUSES: PHYLUM _NEGARNAVIRICOTA_ Jens H. Kuhn* 1 1NIH/NIAID/DCR, INTEGRATED RESEARCH FACILITY AT FORT DETRICK, Frederick, United States Abstract: (-)ssRNA viruses, informally grouped in “Baltimore class V”, are currently classified in the orders Bunyavirales and Mononegavirales, the unassigned families Arenaviridae, Ophioviridae, and Orthomyxoviridae, and the unassigned genus Deltavirus. Recent metagenomic studies revealed the existence of hundreds of novel (-)ssRNA viruses in highly divergent organisms. These viruses either cluster with the existing taxa (e.g., bunyaviruses in citrus, melon, and kinetoplastids; hantaviruses in fish) or are highly divergent (e.g., chǔviruses, qínviruses, yuèviruses). With exception of hepatitis D virus (genus Deltavirus), all these viruses are homophyletically connected via their RNA-dependent RNA polymerases. This connection led to a proposal to the International Committee on Taxonomy of Viruses (ICTV) to replace the unofficial Baltimore class V with a phylum that unifies all current taxa and contains the necessary ranks for classification of all currently described (-)ssRNA viruses excluding hepatitis D virus. I will outline the phylum as recently proposed, present foreseeable and imminent changes to the phylum based on novel discoveries, and discuss current taxonomic challenges. I will explain the taxonomic process from official proposal writing via Study Group deliberations to ICTV Executive Committee decisions. Finally, I will call on the entire (-)ssRNA virology community to become engaged in this process to ensure that classification and nomenclature of all (-)ssRNA viruses is done swiftly, as accurately as possible on an annual basis, and with maximum input from all experts in a transparent manner.

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